686101631 has 4 divisors (see below), whose sum is σ = 690210192. Its totient is φ = 681993072.

The previous prime is 686101621. The next prime is 686101711. The reversal of 686101631 is 136101686.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-686101631 is a prime.

It is a super-2 number, since 2×686101631² = 941470896121720322, 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 (686101601) 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, 2054030 + ... + 2054363.

It is an arithmetic number, because the mean of its divisors is an integer number (172552548).

Almost surely, 2^686101631 is an apocalyptic number.

686101631 is a deficient number, since it is larger than the sum of its proper divisors (4108561).

686101631 is a wasteful number, since it uses less digits than its factorization.

686101631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4108560.

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 686101631 is about 26193.5417803702. The cubic root of 686101631 is about 881.9882861895.

Subtracting from 686101631 its reverse (136101686), we obtain a palindrome (549999945).

The spelling of 686101631 in words is "six hundred eighty-six million, one hundred one thousand, six hundred thirty-one".