111111101221 has 2 divisors, whose sum is σ = 111111101222. Its totient is φ = 111111101220.

The previous prime is 111111101197. The next prime is 111111101303. The reversal of 111111101221 is 122101111111.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 95472348196 + 15638753025 = 308986^2 + 125055^2 .

It is a cyclic number.

It is not a de Polignac number, because 111111101221 - 2³¹ = 108963617573 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111111101921) 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, 55555550610 + 55555550611.

It is an arithmetic number, because the mean of its divisors is an integer number (55555550611).

Almost surely, 2^111111101221 is an apocalyptic number.

It is an amenable number.

111111101221 is a deficient number, since it is larger than the sum of its proper divisors (1).

111111101221 is an equidigital number, since it uses as much as digits as its factorization.

111111101221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4, while the sum is 13.

Adding to 111111101221 its reverse (122101111111), we get a palindrome (233212212332).

The spelling of 111111101221 in words is "one hundred eleven billion, one hundred eleven million, one hundred one thousand, two hundred twenty-one".