645570444 has 48 divisors (see below), whose sum is σ = 1596986496. Its totient is φ = 202272000.

The previous prime is 645570439. The next prime is 645570449. The reversal of 645570444 is 444075546.

It is an interprime number because it is at equal distance from previous prime (645570439) and next prime (645570449).

It is a super-2 number, since 2×645570444² = 833522396332714272, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (645570449) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 212899 + ... + 215909.

It is an arithmetic number, because the mean of its divisors is an integer number (33270552).

Almost surely, 2^645570444 is an apocalyptic number.

It is an amenable number.

645570444 is an abundant number, since it is smaller than the sum of its proper divisors (951416052).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645570444 is a wasteful number, since it uses less digits than its factorization.

645570444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4086 (or 4084 counting only the distinct ones).

The product of its (nonzero) digits is 268800, while the sum is 39.

The square root of 645570444 is about 25408.0783216677. The cubic root of 645570444 is about 864.2668982110.

The spelling of 645570444 in words is "six hundred forty-five million, five hundred seventy thousand, four hundred forty-four".