2161979242961 has 2 divisors, whose sum is σ = 2161979242962. Its totient is φ = 2161979242960.

The previous prime is 2161979242939. The next prime is 2161979242963. The reversal of 2161979242961 is 1692429791612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1433960745361 + 728018497600 = 1197481^2 + 853240^2 .

It is a cyclic number.

It is not a de Polignac number, because 2161979242961 - 2⁶ = 2161979242897 is a prime.

Together with 2161979242963, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2161979242961.

It is not a weakly prime, because it can be changed into another prime (2161979242963) 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, 1080989621480 + 1080989621481.

It is an arithmetic number, because the mean of its divisors is an integer number (1080989621481).

Almost surely, 2^{2161979242961} is an apocalyptic number.

It is an amenable number.

2161979242961 is a deficient number, since it is larger than the sum of its proper divisors (1).

2161979242961 is an equidigital number, since it uses as much as digits as its factorization.

2161979242961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5878656, while the sum is 59.

The spelling of 2161979242961 in words is "two trillion, one hundred sixty-one billion, nine hundred seventy-nine million, two hundred forty-two thousand, nine hundred sixty-one".