645644579 has 4 divisors (see below), whose sum is σ = 646992960. Its totient is φ = 644296200.

The previous prime is 645644563. The next prime is 645644599. The reversal of 645644579 is 975446546.

645644579 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 975446546 = 2 ⋅487723273.

It is a cyclic number.

It is not a de Polignac number, because 645644579 - 2⁴ = 645644563 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645644599) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 673472 + ... + 674429.

It is an arithmetic number, because the mean of its divisors is an integer number (161748240).

Almost surely, 2^645644579 is an apocalyptic number.

645644579 is a deficient number, since it is larger than the sum of its proper divisors (1348381).

645644579 is a wasteful number, since it uses less digits than its factorization.

645644579 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1348380.

The product of its digits is 3628800, while the sum is 50.

The square root of 645644579 is about 25409.5371661902. The cubic root of 645644579 is about 864.2999800508.

The spelling of 645644579 in words is "six hundred forty-five million, six hundred forty-four thousand, five hundred seventy-nine".