644932230642 has 90 divisors (see below), whose sum is σ = 1630570462287. Its totient is φ = 184218651288.

The previous prime is 644932230619. The next prime is 644932230689. The reversal of 644932230642 is 246032239446.

It can be written as a sum of positive squares in only one way, i.e., 322466115321 + 322466115321 = 567861^2 + 567861^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=567861.

It is an unprimeable number.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 166949203 + ... + 166953065.

Almost surely, 2^644932230642 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644932230642

644932230642 is an abundant number, since it is smaller than the sum of its proper divisors (985638231645).

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

644932230642 is an frugal number, since it uses more digits than its factorization.

644932230642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7762 (or 3875 counting only the distinct ones).

The product of its (nonzero) digits is 1492992, while the sum is 45.

The spelling of 644932230642 in words is "six hundred forty-four billion, nine hundred thirty-two million, two hundred thirty thousand, six hundred forty-two".