643255444 has 48 divisors (see below), whose sum is σ = 1271491200. Its totient is φ = 282522240.

The previous prime is 643255433. The next prime is 643255453. The reversal of 643255444 is 444552346.

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 251082 + ... + 253630.

It is an arithmetic number, because the mean of its divisors is an integer number (26489400).

Almost surely, 2^643255444 is an apocalyptic number.

It is an amenable number.

643255444 is a deficient number, since it is larger than the sum of its proper divisors (628235756).

643255444 is a wasteful number, since it uses less digits than its factorization.

643255444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2800 (or 2798 counting only the distinct ones).

The product of its digits is 230400, while the sum is 37.

The square root of 643255444 is about 25362.4810300570. The cubic root of 643255444 is about 863.2325808130.

The spelling of 643255444 in words is "six hundred forty-three million, two hundred fifty-five thousand, four hundred forty-four".