635688 has 56 divisors (see below), whose sum is σ = 1803450. Its totient is φ = 209952.

The previous prime is 635659. The next prime is 635689. The reversal of 635688 is 886536.

It can be written as a sum of positive squares in only one way, i.e., 492804 + 142884 = 702^2 + 378^2 .

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

It is a nialpdrome in base 15.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 635688.

It is not an unprimeable number, because it can be changed into a prime (635689) by changing a digit.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 5778 + ... + 5886.

635688 is a Friedman number, since it can be written as 8*(6^6+5*3^8), using all its digits and the basic arithmetic operations.

2⁶³⁵⁶⁸⁸ 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 635688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (901725).

635688 is an abundant number, since it is smaller than the sum of its proper divisors (1167762).

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

635688 is a wasteful number, since it uses less digits than its factorization.

635688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133 (or 114 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 635688 is about 797.3004452526. The cubic root of 635688 is about 85.9834112586.

The spelling of 635688 in words is "six hundred thirty-five thousand, six hundred eighty-eight".