17966875921 has 4 divisors (see below), whose sum is σ = 17990486244. Its totient is φ = 17943265600.

The previous prime is 17966875919. The next prime is 17966875943. The reversal of 17966875921 is 12957866971.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5808726225 + 12158149696 = 76215^2 + 110264^2 .

It is a cyclic number.

It is not a de Polignac number, because 17966875921 - 2¹ = 17966875919 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 17966875921.

It is not an unprimeable number, because it can be changed into a prime (17966875021) 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, 11804020 + ... + 11805541.

It is an arithmetic number, because the mean of its divisors is an integer number (4497621561).

Almost surely, 2^17966875921 is an apocalyptic number.

It is an amenable number.

17966875921 is a deficient number, since it is larger than the sum of its proper divisors (23610323).

17966875921 is an equidigital number, since it uses as much as digits as its factorization.

17966875921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23610322.

The product of its digits is 11430720, while the sum is 61.

The spelling of 17966875921 in words is "seventeen billion, nine hundred sixty-six million, eight hundred seventy-five thousand, nine hundred twenty-one".