644974583481 has 12 divisors (see below), whose sum is σ = 931651156800. Its totient is φ = 429973269720.

The previous prime is 644974583479. The next prime is 644974583489. The reversal of 644974583481 is 184385479446.

644974583481 is a `hidden beast` number, since 6 + 4 + 4 + 9 + 7 + 4 + 583 + 48 + 1 = 666.

It is not a de Polignac number, because 644974583481 - 2¹ = 644974583479 is a prime.

It is a super-2 number, since 2×644974583481² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (644974583489) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 386181 + ... + 1199618.

It is an arithmetic number, because the mean of its divisors is an integer number (77637596400).

Almost surely, 2^644974583481 is an apocalyptic number.

It is an amenable number.

644974583481 is a deficient number, since it is larger than the sum of its proper divisors (286676573319).

644974583481 is a wasteful number, since it uses less digits than its factorization.

644974583481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1630996 (or 1630993 counting only the distinct ones).

The product of its digits is 92897280, while the sum is 63.

The spelling of 644974583481 in words is "six hundred forty-four billion, nine hundred seventy-four million, five hundred eighty-three thousand, four hundred eighty-one".