21616220443121 has 4 divisors (see below), whose sum is σ = 21647502962544. Its totient is φ = 21584937923700.

The previous prime is 21616220443117. The next prime is 21616220443183. The reversal of 21616220443121 is 12134402261612.

It is a happy number.

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 21616220443121 - 2² = 21616220443117 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21616220443021) 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, 15641258675 + ... + 15641260056.

It is an arithmetic number, because the mean of its divisors is an integer number (5411875740636).

Almost surely, 2^{21616220443121} is an apocalyptic number.

It is an amenable number.

21616220443121 is a deficient number, since it is larger than the sum of its proper divisors (31282519423).

21616220443121 is an equidigital number, since it uses as much as digits as its factorization.

21616220443121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31282519422.

The product of its (nonzero) digits is 27648, while the sum is 35.

The spelling of 21616220443121 in words is "twenty-one trillion, six hundred sixteen billion, two hundred twenty million, four hundred forty-three thousand, one hundred twenty-one".