261628262631 has 12 divisors (see below), whose sum is σ = 391904064552. Its totient is φ = 174418841592.

The previous prime is 261628262443. The next prime is 261628262639. The reversal of 261628262631 is 136262826162.

261628262631 is a `hidden beast` number, since 2 + 6 + 1 + 6 + 2 + 8 + 2 + 6 + 2 + 631 = 666.

It is not a de Polignac number, because 261628262631 - 2¹⁴ = 261628246247 is a prime.

It is a super-2 number, since 2×261628262631² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261628262639) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 538329516 + ... + 538330001.

It is an arithmetic number, because the mean of its divisors is an integer number (32658672046).

Almost surely, 2^261628262631 is an apocalyptic number.

261628262631 is a deficient number, since it is larger than the sum of its proper divisors (130275801921).

261628262631 is an equidigital number, since it uses as much as digits as its factorization.

261628262631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1076659532 (or 1076659520 counting only the distinct ones).

The product of its digits is 497664, while the sum is 45.

The spelling of 261628262631 in words is "two hundred sixty-one billion, six hundred twenty-eight million, two hundred sixty-two thousand, six hundred thirty-one".