640328715 has 144 divisors (see below), whose sum is σ = 1327251744. Its totient is φ = 282839040.

The previous prime is 640328713. The next prime is 640328723. The reversal of 640328715 is 517823046.

640328715 is a `hidden beast` number, since 640 + 3 + 2 + 8 + 7 + 1 + 5 = 666.

It is not a de Polignac number, because 640328715 - 2¹ = 640328713 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 640328715.

It is not an unprimeable number, because it can be changed into a prime (640328713) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 9557112 + ... + 9557178.

It is an arithmetic number, because the mean of its divisors is an integer number (9217026).

Almost surely, 2^640328715 is an apocalyptic number.

640328715 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

640328715 is an abundant number, since it is smaller than the sum of its proper divisors (686923029).

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

640328715 is a wasteful number, since it uses less digits than its factorization.

640328715 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 170 (or 136 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

The square root of 640328715 is about 25304.7172479757. The cubic root of 640328715 is about 861.9213913850.

The spelling of 640328715 in words is "six hundred forty million, three hundred twenty-eight thousand, seven hundred fifteen".