636216644 has 12 divisors (see below), whose sum is σ = 1272433344. Its totient is φ = 272664264.

The previous prime is 636216617. The next prime is 636216649. The reversal of 636216644 is 446612636.

It is a happy number.

636216644 is an admirable number.

It is a junction number, because it is equal to n+sod(n) for n = 636216598 and 636216607.

It is not an unprimeable number, because it can be changed into a prime (636216649) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11360984 + ... + 11361039.

It is an arithmetic number, because the mean of its divisors is an integer number (106036112).

Almost surely, 2^636216644 is an apocalyptic number.

It is an amenable number.

636216644 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

636216644 is a wasteful number, since it uses less digits than its factorization.

636216644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22722034 (or 22722032 counting only the distinct ones).

The product of its digits is 124416, while the sum is 38.

The square root of 636216644 is about 25223.3353068146. The cubic root of 636216644 is about 860.0723952036.

The spelling of 636216644 in words is "six hundred thirty-six million, two hundred sixteen thousand, six hundred forty-four".