644553676887 has 16 divisors (see below), whose sum is σ = 865669770720. Its totient is φ = 426581388800.

The previous prime is 644553676849. The next prime is 644553676891. The reversal of 644553676887 is 788676355446.

It is a cyclic number.

It is not a de Polignac number, because 644553676887 - 2¹⁴ = 644553660503 is a prime.

It is a super-3 number, since 3×644553676887³ (a number of 36 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644553676087) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1194414 + ... + 1647947.

It is an arithmetic number, because the mean of its divisors is an integer number (54104360670).

Almost surely, 2^644553676887 is an apocalyptic number.

644553676887 is a deficient number, since it is larger than the sum of its proper divisors (221116093833).

644553676887 is a wasteful number, since it uses less digits than its factorization.

644553676887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2842914.

The product of its digits is 812851200, while the sum is 69.

The spelling of 644553676887 in words is "six hundred forty-four billion, five hundred fifty-three million, six hundred seventy-six thousand, eight hundred eighty-seven".