261497331 has 24 divisors (see below), whose sum is σ = 391233024. Its totient is φ = 168199920.

The previous prime is 261497329. The next prime is 261497339. The reversal of 261497331 is 133794162.

261497331 is a `hidden beast` number, since 2 + 614 + 9 + 7 + 3 + 31 = 666.

It is not a de Polignac number, because 261497331 - 2¹ = 261497329 is a prime.

It is a super-2 number, since 2×261497331² = 136761708240247122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (261497339) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 25680 + ... + 34386.

It is an arithmetic number, because the mean of its divisors is an integer number (16301376).

Almost surely, 2^261497331 is an apocalyptic number.

261497331 is a deficient number, since it is larger than the sum of its proper divisors (129735693).

261497331 is a wasteful number, since it uses less digits than its factorization.

261497331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8831 (or 8828 counting only the distinct ones).

The product of its digits is 27216, while the sum is 36.

The square root of 261497331 is about 16170.8791041180. The cubic root of 261497331 is about 639.4733060919.

The spelling of 261497331 in words is "two hundred sixty-one million, four hundred ninety-seven thousand, three hundred thirty-one".