637640 has 32 divisors (see below), whose sum is σ = 1512000. Its totient is φ = 241344.

The previous prime is 637627. The next prime is 637657. The reversal of 637640 is 46736.

637640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 341 + ... + 1179.

It is an arithmetic number, because the mean of its divisors is an integer number (47250).

2⁶³⁷⁶⁴⁰ 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 637640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (756000).

637640 is an abundant number, since it is smaller than the sum of its proper divisors (874360).

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

637640 is a wasteful number, since it uses less digits than its factorization.

637640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 869 (or 865 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 26.

The square root of 637640 is about 798.5236377215. The cubic root of 637640 is about 86.0713307605.

The spelling of 637640 in words is "six hundred thirty-seven thousand, six hundred forty".