635680 has 48 divisors (see below), whose sum is σ = 1564920. Its totient is φ = 243712.

The previous prime is 635659. The next prime is 635689. The reversal of 635680 is 86536.

It can be written as a sum of positive squares in 4 ways, for example, as 535824 + 99856 = 732^2 + 316^2 .

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 7 ways as a sum of consecutive naturals, for example, 4572 + ... + 4708.

2⁶³⁵⁶⁸⁰ 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 635680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (782460).

635680 is an abundant number, since it is smaller than the sum of its proper divisors (929240).

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

635680 is a wasteful number, since it uses less digits than its factorization.

635680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 181 (or 173 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 635680 is about 797.2954283075. The cubic root of 635680 is about 85.9830505627.

Adding to 635680 its product of nonzero digits (4320), we get a square (640000 = 800²).

The spelling of 635680 in words is "six hundred thirty-five thousand, six hundred eighty".