643744264 has 16 divisors (see below), whose sum is σ = 1245957120. Its totient is φ = 311489040.

The previous prime is 643744259. The next prime is 643744267. The reversal of 643744264 is 462447346.

It is not an unprimeable number, because it can be changed into a prime (643744267) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1297624 + ... + 1298119.

It is an arithmetic number, because the mean of its divisors is an integer number (77872320).

Almost surely, 2^643744264 is an apocalyptic number.

It is an amenable number.

643744264 is a deficient number, since it is larger than the sum of its proper divisors (602212856).

643744264 is a wasteful number, since it uses less digits than its factorization.

643744264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2595780 (or 2595776 counting only the distinct ones).

The product of its digits is 387072, while the sum is 40.

The square root of 643744264 is about 25372.1158755040. The cubic root of 643744264 is about 863.4511868184.

The spelling of 643744264 in words is "six hundred forty-three million, seven hundred forty-four thousand, two hundred sixty-four".