165891731 has 2 divisors, whose sum is σ = 165891732. Its totient is φ = 165891730.

The previous prime is 165891703. The next prime is 165891743. The reversal of 165891731 is 137198561.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 165891731 - 2⁶ = 165891667 is a prime.

It is a super-2 number, since 2×165891731² = 55040132828352722, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (165891931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82945865 + 82945866.

It is an arithmetic number, because the mean of its divisors is an integer number (82945866).

Almost surely, 2^165891731 is an apocalyptic number.

165891731 is a deficient number, since it is larger than the sum of its proper divisors (1).

165891731 is an equidigital number, since it uses as much as digits as its factorization.

165891731 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 45360, while the sum is 41.

The square root of 165891731 is about 12879.8963893348. The cubic root of 165891731 is about 549.4669557319.

The spelling of 165891731 in words is "one hundred sixty-five million, eight hundred ninety-one thousand, seven hundred thirty-one".