111311021021 has 2 divisors, whose sum is σ = 111311021022. Its totient is φ = 111311021020.

The previous prime is 111311021009. The next prime is 111311021051. The reversal of 111311021021 is 120120113111.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 107755284121 + 3555736900 = 328261^2 + 59630^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-111311021021 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 111311020987 and 111311021005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111311021051) 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, 55655510510 + 55655510511.

It is an arithmetic number, because the mean of its divisors is an integer number (55655510511).

Almost surely, 2^111311021021 is an apocalyptic number.

It is an amenable number.

111311021021 is a deficient number, since it is larger than the sum of its proper divisors (1).

111311021021 is an equidigital number, since it uses as much as digits as its factorization.

111311021021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12, while the sum is 14.

Adding to 111311021021 its reverse (120120113111), we get a palindrome (231431134132).

The spelling of 111311021021 in words is "one hundred eleven billion, three hundred eleven million, twenty-one thousand, twenty-one".