165559081 has 2 divisors, whose sum is σ = 165559082. Its totient is φ = 165559080.

The previous prime is 165559019. The next prime is 165559091. The reversal of 165559081 is 180955561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 133171600 + 32387481 = 11540^2 + 5691^2 .

It is a cyclic number.

It is not a de Polignac number, because 165559081 - 2¹⁵ = 165526313 is a prime.

It is a super-2 number, since 2×165559081² = 54819618603129122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (165559091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82779540 + 82779541.

It is an arithmetic number, because the mean of its divisors is an integer number (82779541).

Almost surely, 2^165559081 is an apocalyptic number.

It is an amenable number.

165559081 is a deficient number, since it is larger than the sum of its proper divisors (1).

165559081 is an equidigital number, since it uses as much as digits as its factorization.

165559081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54000, while the sum is 40.

The square root of 165559081 is about 12866.9763736474. The cubic root of 165559081 is about 549.0994419531.

The spelling of 165559081 in words is "one hundred sixty-five million, five hundred fifty-nine thousand, eighty-one".