21134805121 has 4 divisors (see below), whose sum is σ = 21135121200. Its totient is φ = 21134489044.

The previous prime is 21134805089. The next prime is 21134805191. The reversal of 21134805121 is 12150843112.

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 21134805121 - 2⁵ = 21134805089 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 21134805121.

It is not an unprimeable number, because it can be changed into a prime (21134805191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13951 + ... + 206068.

It is an arithmetic number, because the mean of its divisors is an integer number (5283780300).

Almost surely, 2^21134805121 is an apocalyptic number.

It is an amenable number.

21134805121 is a deficient number, since it is larger than the sum of its proper divisors (316079).

21134805121 is an equidigital number, since it uses as much as digits as its factorization.

21134805121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 316078.

The product of its (nonzero) digits is 1920, while the sum is 28.

It can be divided in two parts, 21134 and 805121, that added together give a triangular number (826255 = T₁₂₈₅).

The spelling of 21134805121 in words is "twenty-one billion, one hundred thirty-four million, eight hundred five thousand, one hundred twenty-one".