165508261 has 2 divisors, whose sum is σ = 165508262. Its totient is φ = 165508260.

The previous prime is 165508237. The next prime is 165508271. The reversal of 165508261 is 162805561.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 165508225 + 36 = 12865^2 + 6^2 .

It is a cyclic number.

It is not a de Polignac number, because 165508261 - 2¹¹ = 165506213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165508271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82754130 + 82754131.

It is an arithmetic number, because the mean of its divisors is an integer number (82754131).

Almost surely, 2^165508261 is an apocalyptic number.

It is an amenable number.

165508261 is a deficient number, since it is larger than the sum of its proper divisors (1).

165508261 is an equidigital number, since it uses as much as digits as its factorization.

165508261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 14400, while the sum is 34.

The square root of 165508261 is about 12865.0013991449. The cubic root of 165508261 is about 549.0432523656.

The spelling of 165508261 in words is "one hundred sixty-five million, five hundred eight thousand, two hundred sixty-one".