643509189 has 12 divisors (see below), whose sum is σ = 933050976. Its totient is φ = 427373352.

The previous prime is 643509179. The next prime is 643509193. The reversal of 643509189 is 981905346.

It is a happy number.

643509189 is a `hidden beast` number, since 64 + 3 + 509 + 1 + 89 = 666.

It is not a de Polignac number, because 643509189 - 2⁸ = 643508933 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643509179) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 133567 + ... + 138300.

It is an arithmetic number, because the mean of its divisors is an integer number (77754248).

Almost surely, 2^643509189 is an apocalyptic number.

It is an amenable number.

643509189 is a deficient number, since it is larger than the sum of its proper divisors (289541787).

643509189 is a wasteful number, since it uses less digits than its factorization.

643509189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 272136 (or 272133 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 45.

The square root of 643509189 is about 25367.4829062720. The cubic root of 643509189 is about 863.3460723545.

The spelling of 643509189 in words is "six hundred forty-three million, five hundred nine thousand, one hundred eighty-nine".