2166990971 has 2 divisors, whose sum is σ = 2166990972. Its totient is φ = 2166990970.

The previous prime is 2166990853. The next prime is 2166990979. The reversal of 2166990971 is 1790996612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2166990971 - 2²⁶ = 2099882107 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (2166990979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1083495485 + 1083495486.

It is an arithmetic number, because the mean of its divisors is an integer number (1083495486).

Almost surely, 2^2166990971 is an apocalyptic number.

2166990971 is a deficient number, since it is larger than the sum of its proper divisors (1).

2166990971 is an equidigital number, since it uses as much as digits as its factorization.

2166990971 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 367416, while the sum is 50.

The square root of 2166990971 is about 46550.9502695702. The cubic root of 2166990971 is about 1294.0539038658.

The spelling of 2166990971 in words is "two billion, one hundred sixty-six million, nine hundred ninety thousand, nine hundred seventy-one".