640971360 has 192 divisors, whose sum is σ = 2341301760. Its totient is φ = 163468800.

The previous prime is 640971343. The next prime is 640971367. The reversal of 640971360 is 63179046.

640971360 is a `hidden beast` number, since 640 + 9 + 7 + 1 + 3 + 6 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640971367) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 96135 + ... + 102585.

It is an arithmetic number, because the mean of its divisors is an integer number (12194280).

Almost surely, 2^640971360 is an apocalyptic number.

640971360 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640971360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1170650880).

640971360 is an abundant number, since it is smaller than the sum of its proper divisors (1700330400).

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

640971360 is a wasteful number, since it uses less digits than its factorization.

640971360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6498 (or 6484 counting only the distinct ones).

The product of its (nonzero) digits is 27216, while the sum is 36.

The square root of 640971360 is about 25317.4121900324. The cubic root of 640971360 is about 862.2096413929.

The spelling of 640971360 in words is "six hundred forty million, nine hundred seventy-one thousand, three hundred sixty".