861554631 has 32 divisors (see below), whose sum is σ = 1372151808. Its totient is φ = 470147040.

The previous prime is 861554597. The next prime is 861554651. The reversal of 861554631 is 136455168.

It is not a de Polignac number, because 861554631 - 2¹⁰ = 861553607 is a prime.

It is a super-2 number, since 2×861554631² = 1484552764395092322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 861554631.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861554651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 427416 + ... + 429426.

It is an arithmetic number, because the mean of its divisors is an integer number (42879744).

Almost surely, 2^861554631 is an apocalyptic number.

861554631 is a deficient number, since it is larger than the sum of its proper divisors (510597177).

861554631 is a wasteful number, since it uses less digits than its factorization.

861554631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2931.

The product of its digits is 86400, while the sum is 39.

The square root of 861554631 is about 29352.2508676933. The cubic root of 861554631 is about 951.5412216256.

The spelling of 861554631 in words is "eight hundred sixty-one million, five hundred fifty-four thousand, six hundred thirty-one".