640719992 has 32 divisors (see below), whose sum is σ = 1313280000. Its totient is φ = 290632800.

The previous prime is 640719991. The next prime is 640720001. The reversal of 640719992 is 299917046.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640719991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36617 + ... + 51207.

It is an arithmetic number, because the mean of its divisors is an integer number (41040000).

Almost surely, 2^640719992 is an apocalyptic number.

It is an amenable number.

640719992 is an abundant number, since it is smaller than the sum of its proper divisors (672560008).

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

640719992 is a wasteful number, since it uses less digits than its factorization.

640719992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15107 (or 15103 counting only the distinct ones).

The product of its (nonzero) digits is 244944, while the sum is 47.

The square root of 640719992 is about 25312.4473727848. The cubic root of 640719992 is about 862.0969165170.

The spelling of 640719992 in words is "six hundred forty million, seven hundred nineteen thousand, nine hundred ninety-two".