636400 has 60 divisors (see below), whose sum is σ = 1606792. Its totient is φ = 241920.

The previous prime is 636359. The next prime is 636403. The reversal of 636400 is 4636.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (636403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14779 + ... + 14821.

2⁶³⁶⁴⁰⁰ 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 636400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (803396).

636400 is an abundant number, since it is smaller than the sum of its proper divisors (970392).

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

636400 is a wasteful number, since it uses less digits than its factorization.

636400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98 (or 87 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 19.

The square root of 636400 is about 797.7468270072. The cubic root of 636400 is about 86.0155010818.

The spelling of 636400 in words is "six hundred thirty-six thousand, four hundred".