645064320 has 128 divisors (see below), whose sum is σ = 2177202240. Its totient is φ = 161890304.

The previous prime is 645064283. The next prime is 645064333. The reversal of 645064320 is 23460546.

It is a tau number, because it is divible by the number of its divisors (128).

It is a super-2 number, since 2×645064320² = 832215953874124800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22759 + ... + 42521.

Almost surely, 2^645064320 is an apocalyptic number.

645064320 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 645064320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1088601120).

645064320 is an abundant number, since it is smaller than the sum of its proper divisors (1532137920).

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

645064320 is a wasteful number, since it uses less digits than its factorization.

645064320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19802 (or 19790 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 30.

The square root of 645064320 is about 25398.1164655964. The cubic root of 645064320 is about 864.0409788520.

The spelling of 645064320 in words is "six hundred forty-five million, sixty-four thousand, three hundred twenty".