636553021664 has 192 divisors, whose sum is σ = 1550414960640. Its totient is φ = 251029463040.

The previous prime is 636553021651. The next prime is 636553021667. The reversal of 636553021664 is 466120355636.

It is a Harshad number since it is a multiple of its sum of digits (47).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (636553021667) 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, 298709879 + ... + 298712009.

It is an arithmetic number, because the mean of its divisors is an integer number (8075077920).

Almost surely, 2^636553021664 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 636553021664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (775207480320).

636553021664 is an abundant number, since it is smaller than the sum of its proper divisors (913861938976).

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

636553021664 is a wasteful number, since it uses less digits than its factorization.

636553021664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3881 (or 3873 counting only the distinct ones).

The product of its (nonzero) digits is 2332800, while the sum is 47.

The spelling of 636553021664 in words is "six hundred thirty-six billion, five hundred fifty-three million, twenty-one thousand, six hundred sixty-four".