644561577101 has 12 divisors (see below), whose sum is σ = 698024618208. Its totient is φ = 594922455504.

The previous prime is 644561577097. The next prime is 644561577137. The reversal of 644561577101 is 101775165446.

It is not a de Polignac number, because 644561577101 - 2² = 644561577097 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644561577151) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1623206 + ... + 1980888.

It is an arithmetic number, because the mean of its divisors is an integer number (58168718184).

Almost surely, 2^644561577101 is an apocalyptic number.

It is an amenable number.

644561577101 is a deficient number, since it is larger than the sum of its proper divisors (53463041107).

644561577101 is a wasteful number, since it uses less digits than its factorization.

644561577101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 368372 (or 368359 counting only the distinct ones).

The product of its (nonzero) digits is 705600, while the sum is 47.

The spelling of 644561577101 in words is "six hundred forty-four billion, five hundred sixty-one million, five hundred seventy-seven thousand, one hundred one".