636685216 has 12 divisors (see below), whose sum is σ = 1253474082. Its totient is φ = 318342592.

The previous prime is 636685213. The next prime is 636685229. The reversal of 636685216 is 612586636.

It can be written as a sum of positive squares in only one way, i.e., 524410000 + 112275216 = 22900^2 + 10596^2 .

It is a hoax number, since the sum of its digits (43) 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 (636685211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9948175 + ... + 9948238.

Almost surely, 2^636685216 is an apocalyptic number.

It is an amenable number.

636685216 is a deficient number, since it is larger than the sum of its proper divisors (616788866).

636685216 is a wasteful number, since it uses less digits than its factorization.

636685216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19896423 (or 19896415 counting only the distinct ones).

The product of its digits is 311040, while the sum is 43.

The square root of 636685216 is about 25232.6220595482. The cubic root of 636685216 is about 860.2834904592.

The spelling of 636685216 in words is "six hundred thirty-six million, six hundred eighty-five thousand, two hundred sixteen".