21221001102121 has 4 divisors (see below), whose sum is σ = 21221057881044. Its totient is φ = 21220944323200.

The previous prime is 21221001102101. The next prime is 21221001102137. The reversal of 21221001102121 is 12120110012212.

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 11893083363225 + 9327917738896 = 3448635^2 + 3054164^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21221001102121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21221001102095 and 21221001102104.

It is not an unprimeable number, because it can be changed into a prime (21221001102101) 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, 27825100 + ... + 28577581.

It is an arithmetic number, because the mean of its divisors is an integer number (5305264470261).

Almost surely, 2^{21221001102121} is an apocalyptic number.

It is an amenable number.

21221001102121 is a deficient number, since it is larger than the sum of its proper divisors (56778923).

21221001102121 is an equidigital number, since it uses as much as digits as its factorization.

21221001102121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56778922.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21221001102121 its reverse (12120110012212), we get a palindrome (33341111114333).

The spelling of 21221001102121 in words is "twenty-one trillion, two hundred twenty-one billion, one million, one hundred two thousand, one hundred twenty-one".