640947550464 has 243 divisors, whose sum is σ = 2002660287537. Its totient is φ = 197060917248.

The previous prime is 640947550421. The next prime is 640947550487. The reversal of 640947550464 is 464055749046.

The square root of 640947550464 is 800592.

It is a perfect power (a square), and thus also a powerful number.

640947550464 is a `hidden beast` number, since 6 + 4 + 0 + 9 + 4 + 75 + 504 + 64 = 666.

It can be written as a sum of positive squares in only one way, i.e., 94814726400 + 546132824064 = 307920^2 + 739008^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 640947550464.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 499568767 + ... + 499570049.

Almost surely, 2^640947550464 is an apocalyptic number.

640947550464 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

640947550464 is the 800592-nd square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640947550464

640947550464 is an abundant number, since it is smaller than the sum of its proper divisors (1361712737073).

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

640947550464 is an equidigital number, since it uses as much as digits as its factorization.

640947550464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2614 (or 1301 counting only the distinct ones).

The product of its (nonzero) digits is 14515200, while the sum is 54.

The spelling of 640947550464 in words is "six hundred forty billion, nine hundred forty-seven million, five hundred fifty thousand, four hundred sixty-four".