645558879 has 24 divisors (see below), whose sum is σ = 1035808560. Its totient is φ = 356168064.

The previous prime is 645558847. The next prime is 645558923. The reversal of 645558879 is 978855546.

It is not a de Polignac number, because 645558879 - 2⁵ = 645558847 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645550879) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 71454 + ... + 79979.

It is an arithmetic number, because the mean of its divisors is an integer number (43158690).

Almost surely, 2^645558879 is an apocalyptic number.

645558879 is a deficient number, since it is larger than the sum of its proper divisors (390249681).

645558879 is a wasteful number, since it uses less digits than its factorization.

645558879 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151479 (or 151472 counting only the distinct ones).

The product of its digits is 12096000, while the sum is 57.

The square root of 645558879 is about 25407.8507355502. The cubic root of 645558879 is about 864.2617372424.

The spelling of 645558879 in words is "six hundred forty-five million, five hundred fifty-eight thousand, eight hundred seventy-nine".