864559631 has 4 divisors (see below), whose sum is σ = 931064232. Its totient is φ = 798055032.

The previous prime is 864559621. The next prime is 864559669. The reversal of 864559631 is 136955468.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 864559631 - 2²² = 860365327 is a prime.

It is a super-2 number, since 2×864559631² = 1494926711109712322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (864559621) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33252281 + ... + 33252306.

It is an arithmetic number, because the mean of its divisors is an integer number (232766058).

Almost surely, 2^864559631 is an apocalyptic number.

864559631 is a deficient number, since it is larger than the sum of its proper divisors (66504601).

864559631 is a wasteful number, since it uses less digits than its factorization.

864559631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66504600.

The product of its digits is 777600, while the sum is 47.

The square root of 864559631 is about 29403.3948890260. The cubic root of 864559631 is about 952.6462254180.

It can be divided in two parts, 8645 and 59631, that multiplied together give a triangular number (515509995 = T₃₂₁₀₉).

The spelling of 864559631 in words is "eight hundred sixty-four million, five hundred fifty-nine thousand, six hundred thirty-one".