645646896 has 80 divisors (see below), whose sum is σ = 1892736000. Its totient is φ = 210629952.

The previous prime is 645646877. The next prime is 645646909. The reversal of 645646896 is 698646546.

645646896 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (54).

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, 4405 + ... + 36203.

It is an arithmetic number, because the mean of its divisors is an integer number (23659200).

Almost surely, 2^645646896 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 645646896, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (946368000).

645646896 is an abundant number, since it is smaller than the sum of its proper divisors (1247089104).

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

645646896 is a wasteful number, since it uses less digits than its factorization.

645646896 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31863 (or 31851 counting only the distinct ones).

The product of its digits is 7464960, while the sum is 54.

The square root of 645646896 is about 25409.5827592662. The cubic root of 645646896 is about 864.3010139430.

The spelling of 645646896 in words is "six hundred forty-five million, six hundred forty-six thousand, eight hundred ninety-six".