861995631 has 8 divisors (see below), whose sum is σ = 1313517184. Its totient is φ = 492568920.

The previous prime is 861995611. The next prime is 861995639. The reversal of 861995631 is 136599168.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 861995631 - 2¹⁰ = 861994607 is a prime.

It is a super-2 number, since 2×861995631² = 1486072935726176322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861995639) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20523685 + ... + 20523726.

It is an arithmetic number, because the mean of its divisors is an integer number (164189648).

Almost surely, 2^861995631 is an apocalyptic number.

861995631 is a deficient number, since it is larger than the sum of its proper divisors (451521553).

861995631 is a wasteful number, since it uses less digits than its factorization.

861995631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41047421.

The product of its digits is 349920, while the sum is 48.

The square root of 861995631 is about 29359.7621073469. The cubic root of 861995631 is about 951.7035476063.

The spelling of 861995631 in words is "eight hundred sixty-one million, nine hundred ninety-five thousand, six hundred thirty-one".