645967715520 has 224 divisors, whose sum is σ = 2060582112000. Its totient is φ = 171450961920.

The previous prime is 645967715501. The next prime is 645967715531. The reversal of 645967715520 is 25517769546.

It is a Smith number, since the sum of its digits (57) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 201674239 + ... + 201677441.

Almost surely, 2^645967715520 is an apocalyptic number.

645967715520 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 645967715520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1030291056000).

645967715520 is an abundant number, since it is smaller than the sum of its proper divisors (1414614396480).

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

645967715520 is a wasteful number, since it uses less digits than its factorization.

645967715520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4143 (or 4133 counting only the distinct ones).

The product of its (nonzero) digits is 15876000, while the sum is 57.

The spelling of 645967715520 in words is "six hundred forty-five billion, nine hundred sixty-seven million, seven hundred fifteen thousand, five hundred twenty".