Every Day Counts
Centred Triangular Prime Days
 
Age: 20,358 days
Date of birth
Your 28th Centred Triangular Prime Day is on
Saturday
when you will be
20,359 days old

A centred triangular prime is a centred triangular number that is prime.

Centred triangular numbers are of the form (3n2 + 3n + 2) / 2

A centred triangular number is a centred figurate number that represents a triangle with a dot in the centre and all other dots surrounding the centre in successive triangular layers.

The figures for the first four centred triangular numbers are shown below:

Remind me, please


Next Prime Events
Day Age
Event
Days Ahead
Year Age
24 Jan 2026
20,359
tomorrow
55
24 Jan 2026
20,359
tomorrow
55
09 Nov 2027
21,013
655
57
13 Nov 2028
21,383
1,025
58
27 Sep 2029
21,701
1,343
59
13 Oct 2031
22,447
2,089
61
13 Oct 2048
28,657
8,299
78
28 Sep 2052
30,103
9,745
82
03 Mar 2072
37,199
16,841
101
08 Feb 2078
39,367
19,009
107
10 Jan 2090
43,721
23,363
119
10 Jun 2103
48,619
28,261
133
04 Oct 2149
65,537
45,179
179
17 Nov 2244
100,279
79,921
274
06 Jun 2268
108,881
88,523
298
09 Mar 2329
131,071
110,713
358
01 Jul 7787
2,124,679
2,104,321
5817
Ordinal
Day Age
Date
Age
1st
19
18 May 1970
0
2nd
31
30 May 1970
0
3rd
109
16 Aug 1970
0
4th
199
14 Nov 1970
0
5th
409
12 Jun 1971
1
6th
571
21 Nov 1971
1
7th
631
20 Jan 1972
1
8th
829
05 Aug 1972
2
9th
1,489
27 May 1974
4
10th
1,999
19 Oct 1975
5
11th
2,341
25 Sep 1976
6
12th
2,971
17 Jun 1978
8
13th
3,529
27 Dec 1979
9
14th
4,621
23 Dec 1982
12
15th
4,789
09 Jun 1983
13
16th
7,039
06 Aug 1989
19
17th
7,669
28 Apr 1991
20
18th
8,779
12 May 1994
24
19th
9,721
09 Dec 1996
26
20th
10,459
17 Dec 1998
28
21st
10,711
26 Aug 1999
29
22nd
13,681
13 Oct 2007
37
23rd
14,851
26 Dec 2010
40
24th
16,069
27 Apr 2014
43
25th
16,381
05 Mar 2015
44
26th
17,659
03 Sep 2018
48
27th
20,011
10 Feb 2025
54
28th
20,359
24 Jan 2026
55
1
29th
23,251
25 Dec 2033
63
30th
25,939
05 May 2041
71
31st
27,541
23 Sep 2045
75
32nd
29,191
31 Mar 2050
79
33rd
29,611
25 May 2051
81
34th
31,321
29 Jan 2056
85
35th
34,429
02 Aug 2064
94
36th
36,739
29 Nov 2070
100
37th
40,099
10 Feb 2080
109
38th
40,591
16 Jun 2081
111
39th
42,589
05 Dec 2086
116