640409712 has 20 divisors (see below), whose sum is σ = 1654391880. Its totient is φ = 213469888.

The previous prime is 640409699. The next prime is 640409713. The reversal of 640409712 is 217904046.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640409713) 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 3 ways as a sum of consecutive naturals, for example, 6670887 + ... + 6670982.

It is an arithmetic number, because the mean of its divisors is an integer number (82719594).

Almost surely, 2^640409712 is an apocalyptic number.

It is an amenable number.

640409712 is an abundant number, since it is smaller than the sum of its proper divisors (1013982168).

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

640409712 is a wasteful number, since it uses less digits than its factorization.

640409712 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13341880 (or 13341874 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 33.

The square root of 640409712 is about 25306.3176301887. The cubic root of 640409712 is about 861.9577321487.

The spelling of 640409712 in words is "six hundred forty million, four hundred nine thousand, seven hundred twelve".