635988 has 12 divisors (see below), whose sum is σ = 1484000. Its totient is φ = 211992.

The previous prime is 635983. The next prime is 635989. The reversal of 635988 is 889536.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×635988² = 808961472288, which contains 22 as substring.

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 635988.

It is not an unprimeable number, because it can be changed into a prime (635981) by changing a digit.

635988 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26488 + ... + 26511.

2⁶³⁵⁹⁸⁸ is an apocalyptic number.

It is an amenable number.

635988 is an abundant number, since it is smaller than the sum of its proper divisors (848012).

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

635988 is a wasteful number, since it uses less digits than its factorization.

635988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53006 (or 53004 counting only the distinct ones).

The product of its digits is 51840, while the sum is 39.

The square root of 635988 is about 797.4885579116. The cubic root of 635988 is about 85.9969351711.

The spelling of 635988 in words is "six hundred thirty-five thousand, nine hundred eighty-eight".