640999460 has 12 divisors (see below), whose sum is σ = 1346098908. Its totient is φ = 256399776.

The previous prime is 640999459. The next prime is 640999477. The reversal of 640999460 is 64999046.

It can be written as a sum of positive squares in 2 ways, for example, as 435306496 + 205692964 = 20864^2 + 14342^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16024967 + ... + 16025006.

It is an arithmetic number, because the mean of its divisors is an integer number (112174909).

Almost surely, 2^640999460 is an apocalyptic number.

It is an amenable number.

640999460 is an abundant number, since it is smaller than the sum of its proper divisors (705099448).

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

640999460 is a wasteful number, since it uses less digits than its factorization.

640999460 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32049982 (or 32049980 counting only the distinct ones).

The product of its (nonzero) digits is 419904, while the sum is 47.

The square root of 640999460 is about 25317.9671379833. The cubic root of 640999460 is about 862.2222408829. Note that the first 4 decimals are identical.

The spelling of 640999460 in words is "six hundred forty million, nine hundred ninety-nine thousand, four hundred sixty".