686637625 has 8 divisors (see below), whose sum is σ = 856923912. Its totient is φ = 549310000.

The previous prime is 686637593. The next prime is 686637659. The reversal of 686637625 is 526736686.

It can be written as a sum of positive squares in 4 ways, for example, as 826281 + 685811344 = 909^2 + 26188^2 .

It is not a de Polignac number, because 686637625 - 2⁵ = 686637593 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2746426 + ... + 2746675.

It is an arithmetic number, because the mean of its divisors is an integer number (107115489).

Almost surely, 2^686637625 is an apocalyptic number.

It is an amenable number.

686637625 is a deficient number, since it is larger than the sum of its proper divisors (170286287).

686637625 is an equidigital number, since it uses as much as digits as its factorization.

686637625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5493116 (or 5493106 counting only the distinct ones).

The product of its digits is 2177280, while the sum is 49.

The square root of 686637625 is about 26203.7711980547. The cubic root of 686637625 is about 882.2179010440.

The spelling of 686637625 in words is "six hundred eighty-six million, six hundred thirty-seven thousand, six hundred twenty-five".