640991248 has 40 divisors (see below), whose sum is σ = 1266722496. Its totient is φ = 314160000.

The previous prime is 640991191. The next prime is 640991249. The reversal of 640991248 is 842199046.

It is not an unprimeable number, because it can be changed into a prime (640991249) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 164523 + ... + 168373.

Almost surely, 2^640991248 is an apocalyptic number.

It is an amenable number.

640991248 is a deficient number, since it is larger than the sum of its proper divisors (625731248).

640991248 is a wasteful number, since it uses less digits than its factorization.

640991248 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4063 (or 4057 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 43.

The square root of 640991248 is about 25317.8049601461. The cubic root of 640991248 is about 862.2185588209.

The spelling of 640991248 in words is "six hundred forty million, nine hundred ninety-one thousand, two hundred forty-eight".