644530813433 has 16 divisors (see below), whose sum is σ = 700216935936. Its totient is φ = 589734129600.

The previous prime is 644530813397. The next prime is 644530813447. The reversal of 644530813433 is 334318035446.

644530813433 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 644530813433 - 2⁸ = 644530813177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644530812433) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 554291 + ... + 1263447.

It is an arithmetic number, because the mean of its divisors is an integer number (43763558496).

Almost surely, 2^644530813433 is an apocalyptic number.

It is an amenable number.

644530813433 is a deficient number, since it is larger than the sum of its proper divisors (55686122503).

644530813433 is a wasteful number, since it uses less digits than its factorization.

644530813433 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 709784.

The product of its (nonzero) digits is 1244160, while the sum is 44.

Adding to 644530813433 its reverse (334318035446), we get a palindrome (978848848879).

The spelling of 644530813433 in words is "six hundred forty-four billion, five hundred thirty million, eight hundred thirteen thousand, four hundred thirty-three".