644974122635 has 16 divisors (see below), whose sum is σ = 781547450112. Its totient is φ = 510943836000.

The previous prime is 644974122599. The next prime is 644974122649. The reversal of 644974122635 is 536221479446.

It is a happy number.

It is not a de Polignac number, because 644974122635 - 2¹⁴ = 644974106251 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 748391 + ... + 1360160.

It is an arithmetic number, because the mean of its divisors is an integer number (48846715632).

Almost surely, 2^644974122635 is an apocalyptic number.

644974122635 is a deficient number, since it is larger than the sum of its proper divisors (136573327477).

644974122635 is a wasteful number, since it uses less digits than its factorization.

644974122635 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2109154.

The product of its digits is 8709120, while the sum is 53.

The spelling of 644974122635 in words is "six hundred forty-four billion, nine hundred seventy-four million, one hundred twenty-two thousand, six hundred thirty-five".