211221020122121 has 2 divisors, whose sum is σ = 211221020122122. Its totient is φ = 211221020122120.

The previous prime is 211221020122097. The next prime is 211221020122127. The reversal of 211221020122121 is 121221020122112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 139106361680896 + 72114658441225 = 11794336^2 + 8492035^2 .

It is a cyclic number.

It is not a de Polignac number, because 211221020122121 - 2³⁰ = 211219946380297 is a prime.

It is a super-2 number, since 2×211221020122121² (a number of 29 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 211221020122093 and 211221020122102.

It is not a weakly prime, because it can be changed into another prime (211221020122127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105610510061060 + 105610510061061.

It is an arithmetic number, because the mean of its divisors is an integer number (105610510061061).

Almost surely, 2^{211221020122121} is an apocalyptic number.

It is an amenable number.

211221020122121 is a deficient number, since it is larger than the sum of its proper divisors (1).

211221020122121 is an equidigital number, since it uses as much as digits as its factorization.

211221020122121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 128, while the sum is 20.

Adding to 211221020122121 its reverse (121221020122112), we get a palindrome (332442040244233).

Subtracting from 211221020122121 its reverse (121221020122112), we obtain a palindrome (90000000000009).

The spelling of 211221020122121 in words is "two hundred eleven trillion, two hundred twenty-one billion, twenty million, one hundred twenty-two thousand, one hundred twenty-one".