686910631 has 4 divisors (see below), whose sum is σ = 749357064. Its totient is φ = 624464200.

The previous prime is 686910613. The next prime is 686910643. The reversal of 686910631 is 136019686.

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 686910631 - 2²³ = 678522023 is a prime.

It is a super-2 number, since 2×686910631² = 943692429961636322, 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 (686910611) 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, 31223200 + ... + 31223221.

It is an arithmetic number, because the mean of its divisors is an integer number (187339266).

Almost surely, 2^686910631 is an apocalyptic number.

686910631 is a deficient number, since it is larger than the sum of its proper divisors (62446433).

686910631 is a wasteful number, since it uses less digits than its factorization.

686910631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62446432.

The product of its (nonzero) digits is 46656, while the sum is 40.

The square root of 686910631 is about 26208.9799687054. The cubic root of 686910631 is about 882.3348083509.

The spelling of 686910631 in words is "six hundred eighty-six million, nine hundred ten thousand, six hundred thirty-one".