2121339391 has 2 divisors, whose sum is σ = 2121339392. Its totient is φ = 2121339390.

The previous prime is 2121339317. The next prime is 2121339421. The reversal of 2121339391 is 1939331212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2121339391 - 2⁷ = 2121339263 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2121339691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1060669695 + 1060669696.

It is an arithmetic number, because the mean of its divisors is an integer number (1060669696).

Almost surely, 2^2121339391 is an apocalyptic number.

2121339391 is a deficient number, since it is larger than the sum of its proper divisors (1).

2121339391 is an equidigital number, since it uses as much as digits as its factorization.

2121339391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8748, while the sum is 34.

The square root of 2121339391 is about 46058.0002931087. Note that the first 3 decimals coincide. The cubic root of 2121339391 is about 1284.9021391356.

The spelling of 2121339391 in words is "two billion, one hundred twenty-one million, three hundred thirty-nine thousand, three hundred ninety-one".