644734669953 has 8 divisors (see below), whose sum is σ = 937795883616. Its totient is φ = 390748284800.

The previous prime is 644734669921. The next prime is 644734669967. The reversal of 644734669953 is 359966437446.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 644734669953 - 2⁵ = 644734669921 is a prime.

It is not an unprimeable number, because it can be changed into a prime (644734669903) 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 7 ways as a sum of consecutive naturals, for example, 9768707088 + ... + 9768707153.

It is an arithmetic number, because the mean of its divisors is an integer number (117224485452).

Almost surely, 2^644734669953 is an apocalyptic number.

It is an amenable number.

644734669953 is a deficient number, since it is larger than the sum of its proper divisors (293061213663).

644734669953 is a wasteful number, since it uses less digits than its factorization.

644734669953 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19537414255.

The product of its digits is 352719360, while the sum is 66.

The spelling of 644734669953 in words is "six hundred forty-four billion, seven hundred thirty-four million, six hundred sixty-nine thousand, nine hundred fifty-three".