2166778699 has 2 divisors, whose sum is σ = 2166778700. Its totient is φ = 2166778698.

The previous prime is 2166778651. The next prime is 2166778721. The reversal of 2166778699 is 9968776612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2166778699 - 2²⁵ = 2133224267 is a prime.

It is not a weakly prime, because it can be changed into another prime (2166778099) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1083389349 + 1083389350.

It is an arithmetic number, because the mean of its divisors is an integer number (1083389350).

Almost surely, 2^2166778699 is an apocalyptic number.

2166778699 is a deficient number, since it is larger than the sum of its proper divisors (1).

2166778699 is an equidigital number, since it uses as much as digits as its factorization.

2166778699 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13716864, while the sum is 61.

The square root of 2166778699 is about 46548.6702173113. The cubic root of 2166778699 is about 1294.0116485936.

The spelling of 2166778699 in words is "two billion, one hundred sixty-six million, seven hundred seventy-eight thousand, six hundred ninety-nine".