635640 has 32 divisors (see below), whose sum is σ = 1907280. Its totient is φ = 169472.

The previous prime is 635639. The next prime is 635653. The reversal of 635640 is 46536.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a nialpdrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 635640.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 2529 + ... + 2768.

2⁶³⁵⁶⁴⁰ is an apocalyptic number.

635640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

635640 is an abundant number, since it is smaller than the sum of its proper divisors (1271640).

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

635640 is a wasteful number, since it uses less digits than its factorization.

635640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5311 (or 5307 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 24.

The square root of 635640 is about 797.2703431083. The cubic root of 635640 is about 85.9812470378.

It can be divided in two parts, 635 and 640, that added together give a triangular number (1275 = T₅₀).

The spelling of 635640 in words is "six hundred thirty-five thousand, six hundred forty".