636494400 has 126 divisors (see below), whose sum is σ = 2262302562. Its totient is φ = 169728000.

The previous prime is 636494393. The next prime is 636494401. The reversal of 636494400 is 4494636.

636494400 is a `hidden beast` number, since 6 + 3 + 649 + 4 + 4 + 0 + 0 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 2663424 + 633830976 = 1632^2 + 25176^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (636494401) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 7701 + ... + 36500.

Almost surely, 2^636494400 is an apocalyptic number.

636494400 is a gapful number since it is divisible by the number (60) 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 636494400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1131151281).

636494400 is an abundant number, since it is smaller than the sum of its proper divisors (1625808162).

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

636494400 is a wasteful number, since it uses less digits than its factorization.

636494400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44229 (or 44211 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 36.

The square root of 636494400 is about 25228.8406392367. The cubic root of 636494400 is about 860.1975389023.

The spelling of 636494400 in words is "six hundred thirty-six million, four hundred ninety-four thousand, four hundred".