645115968 has 336 divisors, whose sum is σ = 2328062400. Its totient is φ = 174182400.

The previous prime is 645115963. The next prime is 645115969. The reversal of 645115968 is 869511546.

645115968 is a `hidden beast` number, since 6 + 4 + 51 + 1 + 596 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (336).

It is a super-2 number, since 2×645115968² = 832349224337154048, which contains 22 as substring.

Its product of digits (259200) is a multiple of the sum of its prime divisors (432).

It is not an unprimeable number, because it can be changed into a prime (645115963) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1608568 + ... + 1608968.

Almost surely, 2^645115968 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645115968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1164031200).

645115968 is an abundant number, since it is smaller than the sum of its proper divisors (1682946432).

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

645115968 is a wasteful number, since it uses less digits than its factorization.

645115968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 455 (or 432 counting only the distinct ones).

The product of its digits is 259200, while the sum is 45.

The square root of 645115968 is about 25399.1332135567. The cubic root of 645115968 is about 864.0640384633.

The spelling of 645115968 in words is "six hundred forty-five million, one hundred fifteen thousand, nine hundred sixty-eight".