165363221 has 4 divisors (see below), whose sum is σ = 165891852. Its totient is φ = 164834592.

The previous prime is 165363217. The next prime is 165363223. The reversal of 165363221 is 122363561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 122363561 = 379 ⋅322859.

It can be written as a sum of positive squares in 2 ways, for example, as 10982596 + 154380625 = 3314^2 + 12425^2 .

It is a cyclic number.

It is not a de Polignac number, because 165363221 - 2² = 165363217 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 (165363223) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 263846 + ... + 264471.

It is an arithmetic number, because the mean of its divisors is an integer number (41472963).

Almost surely, 2^165363221 is an apocalyptic number.

It is an amenable number.

165363221 is a deficient number, since it is larger than the sum of its proper divisors (528631).

165363221 is an equidigital number, since it uses as much as digits as its factorization.

165363221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 528630.

The product of its digits is 6480, while the sum is 29.

The square root of 165363221 is about 12859.3631646361. The cubic root of 165363221 is about 548.8828243083.

The spelling of 165363221 in words is "one hundred sixty-five million, three hundred sixty-three thousand, two hundred twenty-one".