111221221021 has 2 divisors, whose sum is σ = 111221221022. Its totient is φ = 111221221020.

The previous prime is 111221220983. The next prime is 111221221037. The reversal of 111221221021 is 120122122111.

It is an a-pointer prime, because the next prime (111221221037) can be obtained adding 111221221021 to its sum of digits (16).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 110497072921 + 724148100 = 332411^2 + 26910^2 .

It is a cyclic number.

It is not a de Polignac number, because 111221221021 - 2⁷ = 111221220893 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 111221220986 and 111221221004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111221221061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55610610510 + 55610610511.

It is an arithmetic number, because the mean of its divisors is an integer number (55610610511).

Almost surely, 2^111221221021 is an apocalyptic number.

It is an amenable number.

111221221021 is a deficient number, since it is larger than the sum of its proper divisors (1).

111221221021 is an equidigital number, since it uses as much as digits as its factorization.

111221221021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 111221221021 its reverse (120122122111), we get a palindrome (231343343132).

The spelling of 111221221021 in words is "one hundred eleven billion, two hundred twenty-one million, two hundred twenty-one thousand, twenty-one".