686920731 has 8 divisors (see below), whose sum is σ = 1046736384. Its totient is φ = 392526120.

The previous prime is 686920727. The next prime is 686920739. The reversal of 686920731 is 137029686.

It is a happy number.

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

It is not a de Polignac number, because 686920731 - 2² = 686920727 is a prime.

It is a super-2 number, since 2×686920731² = 943720181355148722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (686920739) 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, 16355235 + ... + 16355276.

It is an arithmetic number, because the mean of its divisors is an integer number (130842048).

Almost surely, 2^686920731 is an apocalyptic number.

686920731 is a deficient number, since it is larger than the sum of its proper divisors (359815653).

686920731 is a wasteful number, since it uses less digits than its factorization.

686920731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32710521.

The product of its (nonzero) digits is 108864, while the sum is 42.

The square root of 686920731 is about 26209.1726500475. The cubic root of 686920731 is about 882.3391328038.

The spelling of 686920731 in words is "six hundred eighty-six million, nine hundred twenty thousand, seven hundred thirty-one".