640696608 has 48 divisors (see below), whose sum is σ = 1868700960. Its totient is φ = 213565248.

The previous prime is 640696607. The next prime is 640696613. The reversal of 640696608 is 806696046.

It is a tau number, because it is divible by the number of its divisors (48).

It is not an unprimeable number, because it can be changed into a prime (640696601) 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, 369910 + ... + 371637.

It is an arithmetic number, because the mean of its divisors is an integer number (38931270).

Almost surely, 2^640696608 is an apocalyptic number.

It is an amenable number.

640696608 is an abundant number, since it is smaller than the sum of its proper divisors (1228004352).

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

640696608 is a wasteful number, since it uses less digits than its factorization.

640696608 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 741566 (or 741552 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 45.

The square root of 640696608 is about 25311.9854614370. The cubic root of 640696608 is about 862.0864285660.

The spelling of 640696608 in words is "six hundred forty million, six hundred ninety-six thousand, six hundred eight".