21122220022121 has 4 divisors (see below), whose sum is σ = 22364703552852. Its totient is φ = 19879736491392.

The previous prime is 21122220022039. The next prime is 21122220022139. The reversal of 21122220022121 is 12122002222112.

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 12877052348521 + 8245167673600 = 3588461^2 + 2871440^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21122220022121 is a prime.

It is a super-2 number, since 2×21122220022121² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21122220022093 and 21122220022102.

It is not an unprimeable number, because it can be changed into a prime (21122220027121) 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, 621241765340 + ... + 621241765373.

It is an arithmetic number, because the mean of its divisors is an integer number (5591175888213).

Almost surely, 2^{21122220022121} is an apocalyptic number.

It is an amenable number.

21122220022121 is a deficient number, since it is larger than the sum of its proper divisors (1242483530731).

21122220022121 is a wasteful number, since it uses less digits than its factorization.

21122220022121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1242483530730.

The product of its (nonzero) digits is 256, while the sum is 20.

Adding to 21122220022121 its reverse (12122002222112), we get a palindrome (33244222244233).

The spelling of 21122220022121 in words is "twenty-one trillion, one hundred twenty-two billion, two hundred twenty million, twenty-two thousand, one hundred twenty-one".