645925223 has 4 divisors (see below), whose sum is σ = 647963160. Its totient is φ = 643887288.

The previous prime is 645925213. The next prime is 645925249. The reversal of 645925223 is 322529546.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 322529546 = 2 ⋅161264773.

It is a cyclic number.

It is not a de Polignac number, because 645925223 - 2⁸ = 645924967 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645925213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1018493 + ... + 1019126.

It is an arithmetic number, because the mean of its divisors is an integer number (161990790).

Almost surely, 2^645925223 is an apocalyptic number.

645925223 is a deficient number, since it is larger than the sum of its proper divisors (2037937).

645925223 is a wasteful number, since it uses less digits than its factorization.

645925223 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2037936.

The product of its digits is 129600, while the sum is 38.

The square root of 645925223 is about 25415.0589808483. The cubic root of 645925223 is about 864.4251910803.

The spelling of 645925223 in words is "six hundred forty-five million, nine hundred twenty-five thousand, two hundred twenty-three".