21511652231 has 2 divisors, whose sum is σ = 21511652232. Its totient is φ = 21511652230.

The previous prime is 21511652213. The next prime is 21511652293. The reversal of 21511652231 is 13225611512.

Together with previous prime (21511652213) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21511652231 - 2²² = 21507457927 is a prime.

It is a super-2 number, since 2×21511652231² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21511652194 and 21511652203.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21511652531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10755826115 + 10755826116.

It is an arithmetic number, because the mean of its divisors is an integer number (10755826116).

Almost surely, 2^21511652231 is an apocalyptic number.

21511652231 is a deficient number, since it is larger than the sum of its proper divisors (1).

21511652231 is an equidigital number, since it uses as much as digits as its factorization.

21511652231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3600, while the sum is 29.

The spelling of 21511652231 in words is "twenty-one billion, five hundred eleven million, six hundred fifty-two thousand, two hundred thirty-one".