111111201221021 has 2 divisors, whose sum is σ = 111111201221022. Its totient is φ = 111111201221020.

The previous prime is 111111201220979. The next prime is 111111201221029. The reversal of 111111201221021 is 120122102111111.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 104786730698521 + 6324470522500 = 10236539^2 + 2514850^2 .

It is a cyclic number.

It is not a de Polignac number, because 111111201221021 - 2³⁸ = 110836323314077 is a prime.

It is a super-2 number, since 2×111111201221021² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111111201221029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55555600610510 + 55555600610511.

It is an arithmetic number, because the mean of its divisors is an integer number (55555600610511).

Almost surely, 2^{111111201221021} is an apocalyptic number.

It is an amenable number.

111111201221021 is a deficient number, since it is larger than the sum of its proper divisors (1).

111111201221021 is an equidigital number, since it uses as much as digits as its factorization.

111111201221021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16, while the sum is 17.

Adding to 111111201221021 its reverse (120122102111111), we get a palindrome (231233303332132).

It can be divided in two parts, 11111 and 1201221021, that multiplied together give a palindrome (13346766764331).

The spelling of 111111201221021 in words is "one hundred eleven trillion, one hundred eleven billion, two hundred one million, two hundred twenty-one thousand, twenty-one".