165531257 has 2 divisors, whose sum is σ = 165531258. Its totient is φ = 165531256.

The previous prime is 165531251. The next prime is 165531259. The reversal of 165531257 is 752135561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 83375161 + 82156096 = 9131^2 + 9064^2 .

It is a cyclic number.

It is not a de Polignac number, because 165531257 - 2⁴ = 165531241 is a prime.

Together with 165531259, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (165531251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82765628 + 82765629.

It is an arithmetic number, because the mean of its divisors is an integer number (82765629).

Almost surely, 2^165531257 is an apocalyptic number.

It is an amenable number.

165531257 is a deficient number, since it is larger than the sum of its proper divisors (1).

165531257 is an equidigital number, since it uses as much as digits as its factorization.

165531257 is an evil number, because the sum of its binary digits is even.

The product of its digits is 31500, while the sum is 35.

The square root of 165531257 is about 12865.8951107181. The cubic root of 165531257 is about 549.0686795233.

The spelling of 165531257 in words is "one hundred sixty-five million, five hundred thirty-one thousand, two hundred fifty-seven".