2120111921 has 2 divisors, whose sum is σ = 2120111922. Its totient is φ = 2120111920.

The previous prime is 2120111899. The next prime is 2120111923. The reversal of 2120111921 is 1291110212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1581175696 + 538936225 = 39764^2 + 23215^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2120111921 is a prime.

Together with 2120111923, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 2120111893 and 2120111902.

It is not a weakly prime, because it can be changed into another prime (2120111923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1060055960 + 1060055961.

It is an arithmetic number, because the mean of its divisors is an integer number (1060055961).

Almost surely, 2^2120111921 is an apocalyptic number.

It is an amenable number.

2120111921 is a deficient number, since it is larger than the sum of its proper divisors (1).

2120111921 is an equidigital number, since it uses as much as digits as its factorization.

2120111921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 20.

The square root of 2120111921 is about 46044.6731012394. The cubic root of 2120111921 is about 1284.6542638020.

The spelling of 2120111921 in words is "two billion, one hundred twenty million, one hundred eleven thousand, nine hundred twenty-one".