111111011021221 has 2 divisors, whose sum is σ = 111111011021222. Its totient is φ = 111111011021220.

The previous prime is 111111011021167. The next prime is 111111011021261. The reversal of 111111011021221 is 122120110111111.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 107566975102500 + 3544035918721 = 10371450^2 + 1882561^2 .

It is a cyclic number.

It is not a de Polignac number, because 111111011021221 - 2³⁷ = 110973572067749 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 111111011021195 and 111111011021204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111111011021261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55555505510610 + 55555505510611.

It is an arithmetic number, because the mean of its divisors is an integer number (55555505510611).

Almost surely, 2^{111111011021221} is an apocalyptic number.

It is an amenable number.

111111011021221 is a deficient number, since it is larger than the sum of its proper divisors (1).

111111011021221 is an equidigital number, since it uses as much as digits as its factorization.

111111011021221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8, while the sum is 16.

Adding to 111111011021221 its reverse (122120110111111), we get a palindrome (233231121132332).

The spelling of 111111011021221 in words is "one hundred eleven trillion, one hundred eleven billion, eleven million, twenty-one thousand, two hundred twenty-one".