165038521 has 2 divisors, whose sum is σ = 165038522. Its totient is φ = 165038520.

The previous prime is 165038491. The next prime is 165038527. The reversal of 165038521 is 125830561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 164762896 + 275625 = 12836^2 + 525^2 .

It is an emirp because it is prime and its reverse (125830561) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-165038521 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is not a weakly prime, because it can be changed into another prime (165038527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82519260 + 82519261.

It is an arithmetic number, because the mean of its divisors is an integer number (82519261).

Almost surely, 2^165038521 is an apocalyptic number.

It is an amenable number.

165038521 is a deficient number, since it is larger than the sum of its proper divisors (1).

165038521 is an equidigital number, since it uses as much as digits as its factorization.

165038521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7200, while the sum is 31.

The square root of 165038521 is about 12846.7319190524. The cubic root of 165038521 is about 548.5233347975.

The spelling of 165038521 in words is "one hundred sixty-five million, thirty-eight thousand, five hundred twenty-one".