111111111001021 has 2 divisors, whose sum is σ = 111111111001022. Its totient is φ = 111111111001020.

The previous prime is 111111111000991. The next prime is 111111111001069. The reversal of 111111111001021 is 120100111111111.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 110300111692996 + 810999308025 = 10502386^2 + 900555^2 .

It is a cyclic number.

It is not a de Polignac number, because 111111111001021 - 2³⁹ = 110561355187133 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 111111111000992 and 111111111001010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111111111001081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55555555500510 + 55555555500511.

It is an arithmetic number, because the mean of its divisors is an integer number (55555555500511).

Almost surely, 2^{111111111001021} is an apocalyptic number.

It is an amenable number.

111111111001021 is a deficient number, since it is larger than the sum of its proper divisors (1).

111111111001021 is an equidigital number, since it uses as much as digits as its factorization.

111111111001021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2, while the sum is 13.

Adding to 111111111001021 its reverse (120100111111111), we get a palindrome (231211222112132).

The spelling of 111111111001021 in words is "one hundred eleven trillion, one hundred eleven billion, one hundred eleven million, one thousand, twenty-one".