645265680 has 80 divisors (see below), whose sum is σ = 2025703680. Its totient is φ = 169887744.

The previous prime is 645265637. The next prime is 645265703. The reversal of 645265680 is 86562546.

645265680 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (80).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1944 + ... + 35976.

It is an arithmetic number, because the mean of its divisors is an integer number (25321296).

Almost surely, 2^645265680 is an apocalyptic number.

645265680 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 645265680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1012851840).

645265680 is an abundant number, since it is smaller than the sum of its proper divisors (1380438000).

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

645265680 is a wasteful number, since it uses less digits than its factorization.

645265680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34128 (or 34122 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 42.

The square root of 645265680 is about 25402.0802297765. The cubic root of 645265680 is about 864.1308743792.

The spelling of 645265680 in words is "six hundred forty-five million, two hundred sixty-five thousand, six hundred eighty".