165011261 has 4 divisors (see below), whose sum is σ = 165043872. Its totient is φ = 164978652.

The previous prime is 165011243. The next prime is 165011263. The reversal of 165011261 is 162110561.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 162110561 = 547 ⋅296363.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-165011261 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165011263) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6911 + ... + 19436.

It is an arithmetic number, because the mean of its divisors is an integer number (41260968).

Almost surely, 2^165011261 is an apocalyptic number.

It is an amenable number.

165011261 is a deficient number, since it is larger than the sum of its proper divisors (32611).

165011261 is an equidigital number, since it uses as much as digits as its factorization.

165011261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32610.

The product of its (nonzero) digits is 360, while the sum is 23.

The square root of 165011261 is about 12845.6709050170. The cubic root of 165011261 is about 548.4931326173.

The spelling of 165011261 in words is "one hundred sixty-five million, eleven thousand, two hundred sixty-one".