165868691 has 2 divisors, whose sum is σ = 165868692. Its totient is φ = 165868690.

The previous prime is 165868627. The next prime is 165868733. The reversal of 165868691 is 196868561.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 165868691 - 2⁶ = 165868627 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (165868601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82934345 + 82934346.

It is an arithmetic number, because the mean of its divisors is an integer number (82934346).

Almost surely, 2^165868691 is an apocalyptic number.

165868691 is a deficient number, since it is larger than the sum of its proper divisors (1).

165868691 is an equidigital number, since it uses as much as digits as its factorization.

165868691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 622080, while the sum is 50.

The square root of 165868691 is about 12879.0019411444. The cubic root of 165868691 is about 549.4415168413.

Subtracting from 165868691 its sum of digits (50), we obtain a square (165868641 = 12879²).

The spelling of 165868691 in words is "one hundred sixty-five million, eight hundred sixty-eight thousand, six hundred ninety-one".