644922432000 has 2560 divisors, whose sum is σ = 3073894686720. Its totient is φ = 129392640000.

The previous prime is 644922431981. The next prime is 644922432059. The reversal of 644922432000 is 234229446.

644922432000 is a `hidden beast` number, since 6 + 449 + 2 + 2 + 4 + 3 + 200 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (2560).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 4923071935 + ... + 4923072065.

It is an arithmetic number, because the mean of its divisors is an integer number (1200740112).

Almost surely, 2^644922432000 is an apocalyptic number.

644922432000 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 644922432000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1536947343360).

644922432000 is an abundant number, since it is smaller than the sum of its proper divisors (2428972254720).

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

644922432000 is a wasteful number, since it uses less digits than its factorization.

644922432000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 228 (or 196 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 36.

The spelling of 644922432000 in words is "six hundred forty-four billion, nine hundred twenty-two million, four hundred thirty-two thousand".