636621216 has 192 divisors, whose sum is σ = 2114574336. Its totient is φ = 162892800.

The previous prime is 636621211. The next prime is 636621257. The reversal of 636621216 is 612126636.

It is a super-2 number, since 2×636621216² = 810573145322637312, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (636621211) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 524226 + ... + 525438.

It is an arithmetic number, because the mean of its divisors is an integer number (11013408).

Almost surely, 2^636621216 is an apocalyptic number.

636621216 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 636621216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1057287168).

636621216 is an abundant number, since it is smaller than the sum of its proper divisors (1477953120).

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

636621216 is a wasteful number, since it uses less digits than its factorization.

636621216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1315 (or 1307 counting only the distinct ones).

The product of its digits is 15552, while the sum is 33.

The square root of 636621216 is about 25231.3538281242. The cubic root of 636621216 is about 860.2546640800.

The spelling of 636621216 in words is "six hundred thirty-six million, six hundred twenty-one thousand, two hundred sixteen".