635940864 has 156 divisors (see below), whose sum is σ = 1979731936. Its totient is φ = 195526656.

The previous prime is 635940863. The next prime is 635940871. The reversal of 635940864 is 468049536.

635940864 is a `hidden beast` number, since 635 + 9 + 4 + 0 + 8 + 6 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (156).

It is not an unprimeable number, because it can be changed into a prime (635940863) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 478569 + ... + 479895.

Almost surely, 2^635940864 is an apocalyptic number.

635940864 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 635940864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (989865968).

635940864 is an abundant number, since it is smaller than the sum of its proper divisors (1343791072).

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

635940864 is a wasteful number, since it uses less digits than its factorization.

635940864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1370 (or 1345 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 45.

The square root of 635940864 is about 25217.8679511175. The cubic root of 635940864 is about 859.9481057563.

It can be divided in two parts, 635940 and 864, that added together give a square (636804 = 798²).

The spelling of 635940864 in words is "six hundred thirty-five million, nine hundred forty thousand, eight hundred sixty-four".