635657640 has 128 divisors (see below), whose sum is σ = 1943222400. Its totient is φ = 166323200.

The previous prime is 635657629. The next prime is 635657677. The reversal of 635657640 is 46756536.

It is a junction number, because it is equal to n+sod(n) for n = 635657592 and 635657601.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2169334 + ... + 2169626.

It is an arithmetic number, because the mean of its divisors is an integer number (15181425).

Almost surely, 2^635657640 is an apocalyptic number.

635657640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 635657640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (971611200).

635657640 is an abundant number, since it is smaller than the sum of its proper divisors (1307564760).

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

635657640 is a wasteful number, since it uses less digits than its factorization.

635657640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 587 (or 583 counting only the distinct ones).

The product of its (nonzero) digits is 453600, while the sum is 42.

The square root of 635657640 is about 25212.2517836071. The cubic root of 635657640 is about 859.8204240162.

The spelling of 635657640 in words is "six hundred thirty-five million, six hundred fifty-seven thousand, six hundred forty".