640531294720 has 80 divisors (see below), whose sum is σ = 1536041374560. Its totient is φ = 256167890944.

The previous prime is 640531294687. The next prime is 640531294747. The reversal of 640531294720 is 27492135046.

It is a tau number, because it is divible by the number of its divisors (80).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17397291 + ... + 17434069.

It is an arithmetic number, because the mean of its divisors is an integer number (19200517182).

Almost surely, 2^640531294720 is an apocalyptic number.

It is an amenable number.

640531294720 is an abundant number, since it is smaller than the sum of its proper divisors (895510079840).

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

640531294720 is an equidigital number, since it uses as much as digits as its factorization.

640531294720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43605 (or 43589 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 43.

The spelling of 640531294720 in words is "six hundred forty billion, five hundred thirty-one million, two hundred ninety-four thousand, seven hundred twenty".