640697344 has 99 divisors (see below), whose sum is σ = 1503175557. Its totient is φ = 272154624.

The previous prime is 640697333. The next prime is 640697359. The reversal of 640697344 is 443796046.

The square root of 640697344 is 25312.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 11289600 + 629407744 = 3360^2 + 25088^2 .

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 640697344.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 5669832 + ... + 5669944.

Almost surely, 2^640697344 is an apocalyptic number.

640697344 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

640697344 is the 25312-nd square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640697344

640697344 is an abundant number, since it is smaller than the sum of its proper divisors (862478213).

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

640697344 is an equidigital number, since it uses as much as digits as its factorization.

640697344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 260 (or 122 counting only the distinct ones).

The product of its (nonzero) digits is 435456, while the sum is 43.

The cubic root of 640697344 is about 862.0867586730.

The spelling of 640697344 in words is "six hundred forty million, six hundred ninety-seven thousand, three hundred forty-four".