165728261 has 2 divisors, whose sum is σ = 165728262. Its totient is φ = 165728260.

The previous prime is 165728239. The next prime is 165728267. The reversal of 165728261 is 162827561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 156000100 + 9728161 = 12490^2 + 3119^2 .

It is a cyclic number.

It is not a de Polignac number, because 165728261 - 2⁶ = 165728197 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165728267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82864130 + 82864131.

It is an arithmetic number, because the mean of its divisors is an integer number (82864131).

Almost surely, 2^165728261 is an apocalyptic number.

It is an amenable number.

165728261 is a deficient number, since it is larger than the sum of its proper divisors (1).

165728261 is an equidigital number, since it uses as much as digits as its factorization.

165728261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 40320, while the sum is 38.

The square root of 165728261 is about 12873.5488890981. The cubic root of 165728261 is about 549.2864145194.

The spelling of 165728261 in words is "one hundred sixty-five million, seven hundred twenty-eight thousand, two hundred sixty-one".