111021808921 has 2 divisors, whose sum is σ = 111021808922. Its totient is φ = 111021808920.

The previous prime is 111021808913. The next prime is 111021808927. The reversal of 111021808921 is 129808120111.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 90790729225 + 20231079696 = 301315^2 + 142236^2 .

It is a cyclic number.

It is not a de Polignac number, because 111021808921 - 2³ = 111021808913 is a prime.

It is not a weakly prime, because it can be changed into another prime (111021808927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55510904460 + 55510904461.

It is an arithmetic number, because the mean of its divisors is an integer number (55510904461).

Almost surely, 2^111021808921 is an apocalyptic number.

It is an amenable number.

111021808921 is a deficient number, since it is larger than the sum of its proper divisors (1).

111021808921 is an equidigital number, since it uses as much as digits as its factorization.

111021808921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2304, while the sum is 34.

The spelling of 111021808921 in words is "one hundred eleven billion, twenty-one million, eight hundred eight thousand, nine hundred twenty-one".