636604449390 has 640 divisors, whose sum is σ = 2168276850432. Its totient is φ = 130427781120.

The previous prime is 636604449379. The next prime is 636604449407. The reversal of 636604449390 is 93944406636.

636604449390 is a `hidden beast` number, since 6 + 3 + 6 + 60 + 4 + 4 + 493 + 90 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 319 ways as a sum of consecutive naturals, for example, 945920094 + ... + 945920766.

Almost surely, 2^636604449390 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 636604449390, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1084138425216).

636604449390 is an abundant number, since it is smaller than the sum of its proper divisors (1531672401042).

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

636604449390 is a wasteful number, since it uses less digits than its factorization.

636604449390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1066 (or 1057 counting only the distinct ones).

The product of its (nonzero) digits is 10077696, while the sum is 54.

The spelling of 636604449390 in words is "six hundred thirty-six billion, six hundred four million, four hundred forty-nine thousand, three hundred ninety".