21201121002121 has 2 divisors, whose sum is σ = 21201121002122. Its totient is φ = 21201121002120.

The previous prime is 21201121002097. The next prime is 21201121002211. The reversal of 21201121002121 is 12120012110212.

Together with next prime (21201121002211) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19045054596096 + 2156066406025 = 4364064^2 + 1468355^2 .

It is a cyclic number.

It is not a de Polignac number, because 21201121002121 - 2⁹ = 21201121001609 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21201121002095 and 21201121002104.

It is not a weakly prime, because it can be changed into another prime (21201121002521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600560501060 + 10600560501061.

It is an arithmetic number, because the mean of its divisors is an integer number (10600560501061).

Almost surely, 2^{21201121002121} is an apocalyptic number.

It is an amenable number.

21201121002121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201121002121 is an equidigital number, since it uses as much as digits as its factorization.

21201121002121 is an evil number, because the sum of its binary digits is even.

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

Adding to 21201121002121 its reverse (12120012110212), we get a palindrome (33321133112333).

The spelling of 21201121002121 in words is "twenty-one trillion, two hundred one billion, one hundred twenty-one million, two thousand, one hundred twenty-one".