2120121007891 has 2 divisors, whose sum is σ = 2120121007892. Its totient is φ = 2120121007890.

The previous prime is 2120121007783. The next prime is 2120121007919. The reversal of 2120121007891 is 1987001210212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2120121007891 - 2¹³ = 2120120999699 is a prime.

It is not a weakly prime, because it can be changed into another prime (2120121017891) 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, 1060060503945 + 1060060503946.

It is an arithmetic number, because the mean of its divisors is an integer number (1060060503946).

Almost surely, 2^{2120121007891} is an apocalyptic number.

2120121007891 is a deficient number, since it is larger than the sum of its proper divisors (1).

2120121007891 is an equidigital number, since it uses as much as digits as its factorization.

2120121007891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4032, while the sum is 34.

The spelling of 2120121007891 in words is "two trillion, one hundred twenty billion, one hundred twenty-one million, seven thousand, eight hundred ninety-one".