645254872 has 16 divisors (see below), whose sum is σ = 1251572400. Its totient is φ = 311502240.

The previous prime is 645254851. The next prime is 645254879. The reversal of 645254872 is 278452546.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645254879) 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 3 ways as a sum of consecutive naturals, for example, 1390404 + ... + 1390867.

It is an arithmetic number, because the mean of its divisors is an integer number (78223275).

Almost surely, 2^645254872 is an apocalyptic number.

It is an amenable number.

645254872 is a deficient number, since it is larger than the sum of its proper divisors (606317528).

645254872 is a wasteful number, since it uses less digits than its factorization.

645254872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2781306 (or 2781302 counting only the distinct ones).

The product of its digits is 537600, while the sum is 43.

The square root of 645254872 is about 25401.8674904031. The cubic root of 645254872 is about 864.1260497109.

The spelling of 645254872 in words is "six hundred forty-five million, two hundred fifty-four thousand, eight hundred seventy-two".