644106885471 has 48 divisors (see below), whose sum is σ = 1114670476800. Its totient is φ = 366520892976.

The previous prime is 644106885469. The next prime is 644106885497. The reversal of 644106885471 is 174588601446.

644106885471 is a `hidden beast` number, since 6 + 4 + 4 + 10 + 6 + 88 + 547 + 1 = 666.

It is not a de Polignac number, because 644106885471 - 2¹ = 644106885469 is a prime.

It is a super-3 number, since 3×644106885471³ (a number of 36 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644106885431) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 702325 + ... + 1334718.

It is an arithmetic number, because the mean of its divisors is an integer number (23222301600).

Almost surely, 2^644106885471 is an apocalyptic number.

644106885471 is a deficient number, since it is larger than the sum of its proper divisors (470563591329).

644106885471 is a wasteful number, since it uses less digits than its factorization.

644106885471 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2037305 (or 2037292 counting only the distinct ones).

The product of its (nonzero) digits is 5160960, while the sum is 54.

The spelling of 644106885471 in words is "six hundred forty-four billion, one hundred six million, eight hundred eighty-five thousand, four hundred seventy-one".