636665670 has 80 divisors (see below), whose sum is σ = 1716908688. Its totient is φ = 169283520.

The previous prime is 636665663. The next prime is 636665761. The reversal of 636665670 is 76566636.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 340077 + ... + 341943.

Almost surely, 2^636665670 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 636665670, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (858454344).

636665670 is an abundant number, since it is smaller than the sum of its proper divisors (1080243018).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

636665670 is a wasteful number, since it uses less digits than its factorization.

636665670 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2307 (or 2298 counting only the distinct ones).

The product of its (nonzero) digits is 816480, while the sum is 45.

The square root of 636665670 is about 25232.2347405060. The cubic root of 636665670 is about 860.2746869077.

The spelling of 636665670 in words is "six hundred thirty-six million, six hundred sixty-five thousand, six hundred seventy".