646222645 has 24 divisors (see below), whose sum is σ = 798771096. Its totient is φ = 501792768.

The previous prime is 646222637. The next prime is 646222669. The reversal of 646222645 is 546222646.

It can be written as a sum of positive squares in 4 ways, for example, as 259274404 + 386948241 = 16102^2 + 19671^2 .

It is not a de Polignac number, because 646222645 - 2³ = 646222637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2514357 + ... + 2514613.

It is an arithmetic number, because the mean of its divisors is an integer number (33282129).

Almost surely, 2^646222645 is an apocalyptic number.

It is an amenable number.

646222645 is a deficient number, since it is larger than the sum of its proper divisors (152548451).

646222645 is an equidigital number, since it uses as much as digits as its factorization.

646222645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 501 (or 418 counting only the distinct ones).

The product of its digits is 138240, while the sum is 37.

The square root of 646222645 is about 25420.9096021366. The cubic root of 646222645 is about 864.5578481377.

Subtracting from 646222645 its reverse (546222646), we obtain a palindrome (99999999).

The spelling of 646222645 in words is "six hundred forty-six million, two hundred twenty-two thousand, six hundred forty-five".