640009748 has 24 divisors (see below), whose sum is σ = 1289370432. Its totient is φ = 272286144.

The previous prime is 640009723. The next prime is 640009751. The reversal of 640009748 is 847900046.

It is a happy number.

It is a super-2 number, since 2×640009748² = 819224955070047008, which contains 22 as substring.

It is a congruent number.

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, 79586 + ... + 87257.

It is an arithmetic number, because the mean of its divisors is an integer number (53723768).

Almost surely, 2^640009748 is an apocalyptic number.

It is an amenable number.

640009748 is an abundant number, since it is smaller than the sum of its proper divisors (649360684).

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

640009748 is a wasteful number, since it uses less digits than its factorization.

640009748 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166991 (or 166989 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 38.

The square root of 640009748 is about 25298.4139423799. The cubic root of 640009748 is about 861.7782512883.

The spelling of 640009748 in words is "six hundred forty million, nine thousand, seven hundred forty-eight".