643897975 has 54 divisors (see below), whose sum is σ = 951055944. Its totient is φ = 431172000.

The previous prime is 643897921. The next prime is 643898027. The reversal of 643897975 is 579798346.

643897975 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 643897975 - 2⁷ = 643897847 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 4264150 + ... + 4264300.

Almost surely, 2^643897975 is an apocalyptic number.

643897975 is a deficient number, since it is larger than the sum of its proper divisors (307157969).

643897975 is a wasteful number, since it uses less digits than its factorization.

643897975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 293 (or 222 counting only the distinct ones).

The product of its digits is 11430720, while the sum is 58.

The square root of 643897975 is about 25375.1448271729. The cubic root of 643897975 is about 863.5199052990.

The spelling of 643897975 in words is "six hundred forty-three million, eight hundred ninety-seven thousand, nine hundred seventy-five".