643326666344 has 16 divisors (see below), whose sum is σ = 1206659746500. Its totient is φ = 321550733952.

The previous prime is 643326666271. The next prime is 643326666361. The reversal of 643326666344 is 443666623346.

It can be written as a sum of positive squares in 2 ways, for example, as 617736265444 + 25590400900 = 785962^2 + 159970^2 .

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, 14050619 + ... + 14096330.

Almost surely, 2^643326666344 is an apocalyptic number.

It is an amenable number.

643326666344 is a deficient number, since it is larger than the sum of its proper divisors (563333080156).

643326666344 is a wasteful number, since it uses less digits than its factorization.

643326666344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28149812 (or 28149808 counting only the distinct ones).

The product of its digits is 26873856, while the sum is 53.

The spelling of 643326666344 in words is "six hundred forty-three billion, three hundred twenty-six million, six hundred sixty-six thousand, three hundred forty-four".