644163074172 has 96 divisors (see below), whose sum is σ = 1720239393600. Its totient is φ = 208326297600.

The previous prime is 644163074099. The next prime is 644163074267. The reversal of 644163074172 is 271470361446.

644163074172 is a `hidden beast` number, since 6 + 4 + 4 + 1 + 630 + 7 + 4 + 1 + 7 + 2 = 666.

It is a super-2 number, since 2×644163074172² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 399604 + ... + 1203332.

It is an arithmetic number, because the mean of its divisors is an integer number (17919160350).

Almost surely, 2^644163074172 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 644163074172, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (860119696800).

644163074172 is an abundant number, since it is smaller than the sum of its proper divisors (1076076319428).

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

644163074172 is a wasteful number, since it uses less digits than its factorization.

644163074172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 803964 (or 803956 counting only the distinct ones).

The product of its (nonzero) digits is 677376, while the sum is 45.

The spelling of 644163074172 in words is "six hundred forty-four billion, one hundred sixty-three million, seventy-four thousand, one hundred seventy-two".