21145260921 has 8 divisors (see below), whose sum is σ = 29103154944. Its totient is φ = 13642103760.

The previous prime is 21145260893. The next prime is 21145260953. The reversal of 21145260921 is 12906254112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21145260921 - 2¹⁴ = 21145244537 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21145260971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 113684106 + ... + 113684291.

It is an arithmetic number, because the mean of its divisors is an integer number (3637894368).

Almost surely, 2^21145260921 is an apocalyptic number.

It is an amenable number.

21145260921 is a deficient number, since it is larger than the sum of its proper divisors (7957894023).

21145260921 is a wasteful number, since it uses less digits than its factorization.

21145260921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227368431.

The product of its (nonzero) digits is 8640, while the sum is 33.

The spelling of 21145260921 in words is "twenty-one billion, one hundred forty-five million, two hundred sixty thousand, nine hundred twenty-one".