165665131 has 2 divisors, whose sum is σ = 165665132. Its totient is φ = 165665130.

The previous prime is 165665107. The next prime is 165665167. The reversal of 165665131 is 131566561.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 165665131 - 2⁵ = 165665099 is a prime.

It is a super-4 number, since 4×165665131⁴ (a number of 34 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is not a weakly prime, because it can be changed into another prime (165665431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82832565 + 82832566.

It is an arithmetic number, because the mean of its divisors is an integer number (82832566).

Almost surely, 2^165665131 is an apocalyptic number.

165665131 is a deficient number, since it is larger than the sum of its proper divisors (1).

165665131 is an equidigital number, since it uses as much as digits as its factorization.

165665131 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16200, while the sum is 34.

The square root of 165665131 is about 12871.0967287174. The cubic root of 165665131 is about 549.2166600609.

The spelling of 165665131 in words is "one hundred sixty-five million, six hundred sixty-five thousand, one hundred thirty-one".