644362190064 has 240 divisors, whose sum is σ = 1850219864064. Its totient is φ = 209297088000.

The previous prime is 644362190053. The next prime is 644362190071. The reversal of 644362190064 is 460091263446.

644362190064 is a `hidden beast` number, since 6 + 44 + 362 + 190 + 0 + 64 = 666.

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, 241967197 + ... + 241969859.

Almost surely, 2^644362190064 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 644362190064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (925109932032).

644362190064 is an abundant number, since it is smaller than the sum of its proper divisors (1205857674000).

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

644362190064 is a wasteful number, since it uses less digits than its factorization.

644362190064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3036 (or 3027 counting only the distinct ones).

The product of its (nonzero) digits is 746496, while the sum is 45.

The spelling of 644362190064 in words is "six hundred forty-four billion, three hundred sixty-two million, one hundred ninety thousand, sixty-four".