165947779 has 2 divisors, whose sum is σ = 165947780. Its totient is φ = 165947778.

The previous prime is 165947759. The next prime is 165947797. The reversal of 165947779 is 977749561.

Together with next prime (165947797) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 165947779 - 2²⁷ = 31730051 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (165947759) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82973889 + 82973890.

It is an arithmetic number, because the mean of its divisors is an integer number (82973890).

Almost surely, 2^165947779 is an apocalyptic number.

165947779 is a deficient number, since it is larger than the sum of its proper divisors (1).

165947779 is an equidigital number, since it uses as much as digits as its factorization.

165947779 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3333960, while the sum is 55.

The square root of 165947779 is about 12882.0719994883. The cubic root of 165947779 is about 549.5288295338.

The spelling of 165947779 in words is "one hundred sixty-five million, nine hundred forty-seven thousand, seven hundred seventy-nine".