636920064 has 144 divisors (see below), whose sum is σ = 2054955840. Its totient is φ = 192983040.

The previous prime is 636920047. The next prime is 636920129. The reversal of 636920064 is 460029636.

It is a tau number, because it is divible by the number of its divisors (144).

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

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 71844 + ... + 80220.

Almost surely, 2^636920064 is an apocalyptic number.

636920064 is a gapful number since it is divisible by the number (64) 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 636920064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1027477920).

636920064 is an abundant number, since it is smaller than the sum of its proper divisors (1418035776).

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

636920064 is a wasteful number, since it uses less digits than its factorization.

636920064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8413 (or 8393 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 36.

The square root of 636920064 is about 25237.2752887470. The cubic root of 636920064 is about 860.3892523104.

The spelling of 636920064 in words is "six hundred thirty-six million, nine hundred twenty thousand, sixty-four".