635440 has 60 divisors (see below), whose sum is σ = 1633824. Its totient is φ = 229632.

The previous prime is 635431. The next prime is 635441. The reversal of 635440 is 44536.

It is a hoax number, since the sum of its digits (22) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (635441) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13497 + ... + 13543.

2⁶³⁵⁴⁴⁰ 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 635440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (816912).

635440 is an abundant number, since it is smaller than the sum of its proper divisors (998384).

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

635440 is a wasteful number, since it uses less digits than its factorization.

635440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86 (or 67 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 22.

The square root of 635440 is about 797.1449052713. The cubic root of 635440 is about 85.9722282781.

Adding to 635440 its reverse (44536), we get a palindrome (679976).

The spelling of 635440 in words is "six hundred thirty-five thousand, four hundred forty".