165202221 has 4 divisors (see below), whose sum is σ = 220269632. Its totient is φ = 110134812.

The previous prime is 165202181. The next prime is 165202223. The reversal of 165202221 is 122202561.

It is a happy number.

165202221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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.

It is not a de Polignac number, because 165202221 - 2⁶ = 165202157 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165202223) 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, 27533701 + ... + 27533706.

It is an arithmetic number, because the mean of its divisors is an integer number (55067408).

Almost surely, 2^165202221 is an apocalyptic number.

It is an amenable number.

165202221 is a deficient number, since it is larger than the sum of its proper divisors (55067411).

165202221 is an equidigital number, since it uses as much as digits as its factorization.

165202221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55067410.

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 165202221 is about 12853.1016101173. The cubic root of 165202221 is about 548.7046330733.

Adding to 165202221 its reverse (122202561), we get a palindrome (287404782).

The spelling of 165202221 in words is "one hundred sixty-five million, two hundred two thousand, two hundred twenty-one".