636403216 has 40 divisors (see below), whose sum is σ = 1285266944. Its totient is φ = 304922880.

The previous prime is 636403213. The next prime is 636403217. The reversal of 636403216 is 612304636.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is not an unprimeable number, because it can be changed into a prime (636403213) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44860 + ... + 57316.

Almost surely, 2^636403216 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 636403216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (642633472).

636403216 is an abundant number, since it is smaller than the sum of its proper divisors (648863728).

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

636403216 is a wasteful number, since it uses less digits than its factorization.

636403216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12599 (or 12593 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 31.

The square root of 636403216 is about 25227.0334363754. The cubic root of 636403216 is about 860.1564597254.

The spelling of 636403216 in words is "six hundred thirty-six million, four hundred three thousand, two hundred sixteen".