636390657 has 48 divisors (see below), whose sum is σ = 1102233600. Its totient is φ = 345936096.

The previous prime is 636390637. The next prime is 636390701. The reversal of 636390657 is 756093636.

636390657 is a `hidden beast` number, since 6 + 3 + 639 + 0 + 6 + 5 + 7 = 666.

It is not a de Polignac number, because 636390657 - 2²² = 632196353 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (636390607) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 287248 + ... + 289454.

It is an arithmetic number, because the mean of its divisors is an integer number (22963200).

Almost surely, 2^636390657 is an apocalyptic number.

It is an amenable number.

636390657 is a deficient number, since it is larger than the sum of its proper divisors (465842943).

636390657 is a wasteful number, since it uses less digits than its factorization.

636390657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2442 (or 2439 counting only the distinct ones).

The product of its (nonzero) digits is 612360, while the sum is 45.

The square root of 636390657 is about 25226.7845156691. The cubic root of 636390657 is about 860.1508014803.

It can be divided in two parts, 6363 and 90657, that added together give a triangular number (97020 = T₄₄₀).

The spelling of 636390657 in words is "six hundred thirty-six million, three hundred ninety thousand, six hundred fifty-seven".