643974272 has 24 divisors (see below), whose sum is σ = 1283489715. Its totient is φ = 321843584.

The previous prime is 643974269. The next prime is 643974293. The reversal of 643974272 is 272479346.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in only one way, i.e., 321987136 + 321987136 = 17944^2 + 17944^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=17944.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 285983 + ... + 288225.

Almost surely, 2^643974272 is an apocalyptic number.

It is an amenable number.

643974272 is a deficient number, since it is larger than the sum of its proper divisors (639515443).

643974272 is an frugal number, since it uses more digits than its factorization.

643974272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4500 (or 2245 counting only the distinct ones).

The product of its digits is 508032, while the sum is 44.

The square root of 643974272 is about 25376.6481632228. The cubic root of 643974272 is about 863.5540107933.

Multiplying 643974272 by its product of digits (508032), we get a square (327159537352704 = 18087552²).

The spelling of 643974272 in words is "six hundred forty-three million, nine hundred seventy-four thousand, two hundred seventy-two".