644680629527 has 24 divisors (see below), whose sum is σ = 711277969248. Its totient is φ = 583875040320.

The previous prime is 644680629499. The next prime is 644680629553. The reversal of 644680629527 is 725926086446.

It is a happy number.

It is not a de Polignac number, because 644680629527 - 2²⁸ = 644412194071 is a prime.

It is a super-2 number, since 2×644680629527² (a number of 24 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (59) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644680629127) 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 23 ways as a sum of consecutive naturals, for example, 44990438 + ... + 45004764.

It is an arithmetic number, because the mean of its divisors is an integer number (29636582052).

Almost surely, 2^644680629527 is an apocalyptic number.

644680629527 is a deficient number, since it is larger than the sum of its proper divisors (66597339721).

644680629527 is a wasteful number, since it uses less digits than its factorization.

644680629527 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15719 (or 15708 counting only the distinct ones).

The product of its (nonzero) digits is 34836480, while the sum is 59.

The spelling of 644680629527 in words is "six hundred forty-four billion, six hundred eighty million, six hundred twenty-nine thousand, five hundred twenty-seven".