644731870511 has 8 divisors (see below), whose sum is σ = 672776801664. Its totient is φ = 616688031960.

The previous prime is 644731870459. The next prime is 644731870529. The reversal of 644731870511 is 115078137446.

644731870511 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 644731870511 - 2²⁶ = 644664761647 is a prime.

It is a super-2 number, since 2×644731870511² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644731870561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1074140 + ... + 1563086.

It is an arithmetic number, because the mean of its divisors is an integer number (84097100208).

Almost surely, 2^644731870511 is an apocalyptic number.

644731870511 is a deficient number, since it is larger than the sum of its proper divisors (28044931153).

644731870511 is a wasteful number, since it uses less digits than its factorization.

644731870511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 546301.

The product of its (nonzero) digits is 564480, while the sum is 47.

The spelling of 644731870511 in words is "six hundred forty-four billion, seven hundred thirty-one million, eight hundred seventy thousand, five hundred eleven".