261636403231 has 32 divisors (see below), whose sum is σ = 321882739200. Its totient is φ = 207906168960.

The previous prime is 261636403229. The next prime is 261636403261. The reversal of 261636403231 is 132304636162.

It is not a de Polignac number, because 261636403231 - 2¹ = 261636403229 is a prime.

It is a super-2 number, since 2×261636403231² (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 (261636403211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 261001 + ... + 769021.

It is an arithmetic number, because the mean of its divisors is an integer number (10058835600).

Almost surely, 2^261636403231 is an apocalyptic number.

261636403231 is a deficient number, since it is larger than the sum of its proper divisors (60246335969).

261636403231 is a wasteful number, since it uses less digits than its factorization.

261636403231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 508159.

The product of its (nonzero) digits is 93312, while the sum is 37.

The spelling of 261636403231 in words is "two hundred sixty-one billion, six hundred thirty-six million, four hundred three thousand, two hundred thirty-one".