111111122121221 has 2 divisors, whose sum is σ = 111111122121222. Its totient is φ = 111111122121220.

The previous prime is 111111122121187. The next prime is 111111122121227. The reversal of 111111122121221 is 122121221111111.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 105116606464321 + 5994515656900 = 10252639^2 + 2448370^2 .

It is a cyclic number.

It is not a de Polignac number, because 111111122121221 - 2⁶ = 111111122121157 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 111111122121193 and 111111122121202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111111122121227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55555561060610 + 55555561060611.

It is an arithmetic number, because the mean of its divisors is an integer number (55555561060611).

Almost surely, 2^{111111122121221} is an apocalyptic number.

It is an amenable number.

111111122121221 is a deficient number, since it is larger than the sum of its proper divisors (1).

111111122121221 is an equidigital number, since it uses as much as digits as its factorization.

111111122121221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32, while the sum is 20.

Adding to 111111122121221 its reverse (122121221111111), we get a palindrome (233232343232332).

The spelling of 111111122121221 in words is "one hundred eleven trillion, one hundred eleven billion, one hundred twenty-two million, one hundred twenty-one thousand, two hundred twenty-one".