636371221892 has 96 divisors (see below), whose sum is σ = 1320581283840. Its totient is φ = 262573925760.

The previous prime is 636371221883. The next prime is 636371221907. The reversal of 636371221892 is 298122173636.

It is a self number, because there is not a number n which added to its sum of digits gives 636371221892.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 145520618 + ... + 145524990.

It is an arithmetic number, because the mean of its divisors is an integer number (13756055040).

Almost surely, 2^636371221892 is an apocalyptic number.

636371221892 is a gapful number since it is divisible by the number (62) 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 636371221892, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (660290641920).

636371221892 is an abundant number, since it is smaller than the sum of its proper divisors (684210061948).

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

636371221892 is a wasteful number, since it uses less digits than its factorization.

636371221892 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5241 (or 5239 counting only the distinct ones).

The product of its digits is 1306368, while the sum is 50.

The spelling of 636371221892 in words is "six hundred thirty-six billion, three hundred seventy-one million, two hundred twenty-one thousand, eight hundred ninety-two".