165666541 has 2 divisors, whose sum is σ = 165666542. Its totient is φ = 165666540.

The previous prime is 165666521. The next prime is 165666551. The reversal of 165666541 is 145666561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 138156516 + 27510025 = 11754^2 + 5245^2 .

It is a cyclic number.

It is not a de Polignac number, because 165666541 - 2¹¹ = 165664493 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 165666494 and 165666503.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165666521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82833270 + 82833271.

It is an arithmetic number, because the mean of its divisors is an integer number (82833271).

Almost surely, 2^165666541 is an apocalyptic number.

It is an amenable number.

165666541 is a deficient number, since it is larger than the sum of its proper divisors (1).

165666541 is an equidigital number, since it uses as much as digits as its factorization.

165666541 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 129600, while the sum is 40.

The square root of 165666541 is about 12871.1515024880. The cubic root of 165666541 is about 549.2182182107.

The spelling of 165666541 in words is "one hundred sixty-five million, six hundred sixty-six thousand, five hundred forty-one".