645844684800 has 624 divisors, whose sum is σ = 2452754977920. Its totient is φ = 146874040320.

The previous prime is 645844684699. The next prime is 645844684843. The reversal of 645844684800 is 8486448546.

It is a super-2 number, since 2×645844684800² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 501042556 + ... + 501043844.

It is an arithmetic number, because the mean of its divisors is an integer number (3930697080).

Almost surely, 2^645844684800 is an apocalyptic number.

645844684800 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 645844684800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1226377488960).

645844684800 is an abundant number, since it is smaller than the sum of its proper divisors (1806910293120).

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

645844684800 is a wasteful number, since it uses less digits than its factorization.

645844684800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1566 (or 1539 counting only the distinct ones).

The product of its (nonzero) digits is 23592960, while the sum is 57.

The spelling of 645844684800 in words is "six hundred forty-five billion, eight hundred forty-four million, six hundred eighty-four thousand, eight hundred".