165066921 has 6 divisors (see below), whose sum is σ = 238430010. Its totient is φ = 110044608.

The previous prime is 165066919. The next prime is 165066947. The reversal of 165066921 is 129660561.

It can be written as a sum of positive squares in only one way, i.e., 163712025 + 1354896 = 12795^2 + 1164^2 .

It is not a de Polignac number, because 165066921 - 2¹ = 165066919 is a prime.

It is not an unprimeable number, because it can be changed into a prime (165066911) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 9170376 + ... + 9170393.

It is an arithmetic number, because the mean of its divisors is an integer number (39738335).

Almost surely, 2^165066921 is an apocalyptic number.

It is an amenable number.

165066921 is a deficient number, since it is larger than the sum of its proper divisors (73363089).

165066921 is a wasteful number, since it uses less digits than its factorization.

165066921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18340775 (or 18340772 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 36.

The square root of 165066921 is about 12847.8372109861. The cubic root of 165066921 is about 548.5547964812.

The spelling of 165066921 in words is "one hundred sixty-five million, sixty-six thousand, nine hundred twenty-one".