21221102011121 has 4 divisors (see below), whose sum is σ = 21239898382500. Its totient is φ = 21202305639744.

The previous prime is 21221102011097. The next prime is 21221102011127. The reversal of 21221102011121 is 12111020112212.

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 5377000394896 + 15844101616225 = 2318836^2 + 3980465^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221102011121 - 2³⁸ = 20946224104177 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 21221102011121.

It is not an unprimeable number, because it can be changed into a prime (21221102011127) 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, 9398183996 + ... + 9398186253.

It is an arithmetic number, because the mean of its divisors is an integer number (5309974595625).

Almost surely, 2^{21221102011121} is an apocalyptic number.

It is an amenable number.

21221102011121 is a deficient number, since it is larger than the sum of its proper divisors (18796371379).

21221102011121 is a wasteful number, since it uses less digits than its factorization.

21221102011121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18796371378.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21221102011121 its reverse (12111020112212), we get a palindrome (33332122123333).

The spelling of 21221102011121 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred two million, eleven thousand, one hundred twenty-one".