644888083085 has 4 divisors (see below), whose sum is σ = 773865699708. Its totient is φ = 515910466464.

The previous prime is 644888083079. The next prime is 644888083123. The reversal of 644888083085 is 580380888446.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 103130257321 + 541757825764 = 321139^2 + 736042^2 .

It is a cyclic number.

It is not a de Polignac number, because 644888083085 - 2¹⁴ = 644888066701 is a prime.

It is a Duffinian number.

It is a congruent 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 3 ways as a sum of consecutive naturals, for example, 64488808304 + ... + 64488808313.

It is an arithmetic number, because the mean of its divisors is an integer number (193466424927).

Almost surely, 2^644888083085 is an apocalyptic number.

It is an amenable number.

644888083085 is a deficient number, since it is larger than the sum of its proper divisors (128977616623).

644888083085 is a wasteful number, since it uses less digits than its factorization.

644888083085 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128977616622.

The product of its (nonzero) digits is 47185920, while the sum is 62.

The spelling of 644888083085 in words is "six hundred forty-four billion, eight hundred eighty-eight million, eighty-three thousand, eighty-five".