686549457531 has 30 divisors (see below), whose sum is σ = 1156894172980. Its totient is φ = 392313963384.

The previous prime is 686549457527. The next prime is 686549457547. The reversal of 686549457531 is 135754945686.

It is a happy number.

686549457531 is a `hidden beast` number, since 6 + 8 + 6 + 5 + 4 + 94 + 5 + 7 + 531 = 666.

It is not a de Polignac number, because 686549457531 - 2² = 686549457527 is a prime.

It is a super-2 number, since 2×686549457531² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (686549457431) by changing a digit.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 15864121 + ... + 15907338.

Almost surely, 2^686549457531 is an apocalyptic number.

686549457531 is a deficient number, since it is larger than the sum of its proper divisors (470344715449).

686549457531 is an equidigital number, since it uses as much as digits as its factorization.

686549457531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31771493 (or 31771469 counting only the distinct ones).

The product of its digits is 108864000, while the sum is 63.

The spelling of 686549457531 in words is "six hundred eighty-six billion, five hundred forty-nine million, four hundred fifty-seven thousand, five hundred thirty-one".