644049161632 has 12 divisors (see below), whose sum is σ = 1267971787026. Its totient is φ = 322024580800.

The previous prime is 644049161629. The next prime is 644049161633. The reversal of 644049161632 is 236161940446.

It can be written as a sum of positive squares in only one way, i.e., 416752878096 + 227296283536 = 645564^2 + 476756^2 .

It is not an unprimeable number, because it can be changed into a prime (644049161633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10063268119 + ... + 10063268182.

Almost surely, 2^644049161632 is an apocalyptic number.

It is an amenable number.

644049161632 is a deficient number, since it is larger than the sum of its proper divisors (623922625394).

644049161632 is a wasteful number, since it uses less digits than its factorization.

644049161632 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20126536311 (or 20126536303 counting only the distinct ones).

The product of its (nonzero) digits is 746496, while the sum is 46.

The spelling of 644049161632 in words is "six hundred forty-four billion, forty-nine million, one hundred sixty-one thousand, six hundred thirty-two".