645669523 has 2 divisors, whose sum is σ = 645669524. Its totient is φ = 645669522.

The previous prime is 645669511. The next prime is 645669529. The reversal of 645669523 is 325966546.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 645669523 - 2⁵ = 645669491 is a prime.

It is not a weakly prime, because it can be changed into another prime (645669529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322834761 + 322834762.

It is an arithmetic number, because the mean of its divisors is an integer number (322834762).

Almost surely, 2^645669523 is an apocalyptic number.

645669523 is a deficient number, since it is larger than the sum of its proper divisors (1).

645669523 is an equidigital number, since it uses as much as digits as its factorization.

645669523 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1166400, while the sum is 46.

The square root of 645669523 is about 25410.0280007717. The cubic root of 645669523 is about 864.3111104373.

The spelling of 645669523 in words is "six hundred forty-five million, six hundred sixty-nine thousand, five hundred twenty-three".