645687244800 has 2304 divisors, whose sum is σ = 2820819456000. Its totient is φ = 143327232000.

The previous prime is 645687244771. The next prime is 645687244841. The reversal of 645687244800 is 8442786546.

It is a happy number.

645687244800 is a `hidden beast` number, since 6 + 4 + 568 + 72 + 4 + 4 + 8 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (2304).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 10585036770 + ... + 10585036830.

It is an arithmetic number, because the mean of its divisors is an integer number (1224314000).

Almost surely, 2^645687244800 is an apocalyptic number.

645687244800 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 645687244800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1410409728000).

645687244800 is an abundant number, since it is smaller than the sum of its proper divisors (2175132211200).

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

645687244800 is a wasteful number, since it uses less digits than its factorization.

645687244800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165 (or 134 counting only the distinct ones).

The product of its (nonzero) digits is 10321920, while the sum is 54.

The spelling of 645687244800 in words is "six hundred forty-five billion, six hundred eighty-seven million, two hundred forty-four thousand, eight hundred".