165870791 has 2 divisors, whose sum is σ = 165870792. Its totient is φ = 165870790.

The previous prime is 165870721. The next prime is 165870799. The reversal of 165870791 is 197078561.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 165870791 - 2¹⁴ = 165854407 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165870799) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82935395 + 82935396.

It is an arithmetic number, because the mean of its divisors is an integer number (82935396).

Almost surely, 2^165870791 is an apocalyptic number.

165870791 is a deficient number, since it is larger than the sum of its proper divisors (1).

165870791 is an equidigital number, since it uses as much as digits as its factorization.

165870791 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 105840, while the sum is 44.

The square root of 165870791 is about 12879.0834689430. The cubic root of 165870791 is about 549.4438355878.

It can be divided in two parts, 165870 and 791, that added together give a palindrome (166661).

The spelling of 165870791 in words is "one hundred sixty-five million, eight hundred seventy thousand, seven hundred ninety-one".