18221032210021 has 4 divisors (see below), whose sum is σ = 18425762909100. Its totient is φ = 18016301510944.

The previous prime is 18221032209979. The next prime is 18221032210033. The reversal of 18221032210021 is 12001223012281.

It is a happy number.

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 6350974572996 + 11870057637025 = 2520114^2 + 3445295^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18221032210021 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 (18221032216021) 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, 102365349406 + ... + 102365349583.

It is an arithmetic number, because the mean of its divisors is an integer number (4606440727275).

Almost surely, 2^{18221032210021} is an apocalyptic number.

It is an amenable number.

18221032210021 is a deficient number, since it is larger than the sum of its proper divisors (204730699079).

18221032210021 is an equidigital number, since it uses as much as digits as its factorization.

18221032210021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 204730699078.

The product of its (nonzero) digits is 768, while the sum is 25.

The spelling of 18221032210021 in words is "eighteen trillion, two hundred twenty-one billion, thirty-two million, two hundred ten thousand, twenty-one".