2163779921 has 2 divisors, whose sum is σ = 2163779922. Its totient is φ = 2163779920.

The previous prime is 2163779867. The next prime is 2163779923. The reversal of 2163779921 is 1299773612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1349533696 + 814246225 = 36736^2 + 28535^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2163779921 is a prime.

Together with 2163779923, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (2163779923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1081889960 + 1081889961.

It is an arithmetic number, because the mean of its divisors is an integer number (1081889961).

Almost surely, 2^2163779921 is an apocalyptic number.

It is an amenable number.

2163779921 is a deficient number, since it is larger than the sum of its proper divisors (1).

2163779921 is an equidigital number, since it uses as much as digits as its factorization.

2163779921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 285768, while the sum is 47.

The square root of 2163779921 is about 46516.4478544955. The cubic root of 2163779921 is about 1293.4144109831.

The spelling of 2163779921 in words is "two billion, one hundred sixty-three million, seven hundred seventy-nine thousand, nine hundred twenty-one".