6443875021 has 4 divisors (see below), whose sum is σ = 6444071200. Its totient is φ = 6443678844.

The previous prime is 6443875001. The next prime is 6443875027. The reversal of 6443875021 is 1205783446.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 6443875021 - 2⁵ = 6443874989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6443875027) 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, 35511 + ... + 118948.

It is an arithmetic number, because the mean of its divisors is an integer number (1611017800).

Almost surely, 2^6443875021 is an apocalyptic number.

It is an amenable number.

6443875021 is a deficient number, since it is larger than the sum of its proper divisors (196179).

6443875021 is a wasteful number, since it uses less digits than its factorization.

6443875021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196178.

The product of its (nonzero) digits is 161280, while the sum is 40.

The square root of 6443875021 is about 80273.7505103630. The cubic root of 6443875021 is about 1860.8685792794.

The spelling of 6443875021 in words is "six billion, four hundred forty-three million, eight hundred seventy-five thousand, twenty-one".