2121979 has 2 divisors, whose sum is σ = 2121980. Its totient is φ = 2121978.

The previous prime is 2121967. The next prime is 2121989. The reversal of 2121979 is 9791212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2121979 - 2¹⁵ = 2089211 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2121979.

It is not a weakly prime, because it can be changed into another prime (2121989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1060989 + 1060990.

It is an arithmetic number, because the mean of its divisors is an integer number (1060990).

2^2121979 is an apocalyptic number.

2121979 is a deficient number, since it is larger than the sum of its proper divisors (1).

2121979 is an equidigital number, since it uses as much as digits as its factorization.

2121979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2268, while the sum is 31.

The square root of 2121979 is about 1456.7014107222. The cubic root of 2121979 is about 128.5031263906.

The spelling of 2121979 in words is "two million, one hundred twenty-one thousand, nine hundred seventy-nine".