645224644 has 12 divisors (see below), whose sum is σ = 1134876204. Its totient is φ = 320974304.

The previous prime is 645224623. The next prime is 645224711. The reversal of 645224644 is 446422546.

It can be written as a sum of positive squares in 2 ways, for example, as 541958400 + 103266244 = 23280^2 + 10162^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 408619 + ... + 410194.

It is an arithmetic number, because the mean of its divisors is an integer number (94573017).

Almost surely, 2^645224644 is an apocalyptic number.

It is an amenable number.

645224644 is a deficient number, since it is larger than the sum of its proper divisors (489651560).

645224644 is a wasteful number, since it uses less digits than its factorization.

645224644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 819014 (or 819012 counting only the distinct ones).

The product of its digits is 184320, while the sum is 37.

The square root of 645224644 is about 25401.2724878105. The cubic root of 645224644 is about 864.1125557096.

The spelling of 645224644 in words is "six hundred forty-five million, two hundred twenty-four thousand, six hundred forty-four".