165221201 has 4 divisors (see below), whose sum is σ = 166234992. Its totient is φ = 164207412.

The previous prime is 165221197. The next prime is 165221209. The reversal of 165221201 is 102122561.

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 a cyclic number.

It is not a de Polignac number, because 165221201 - 2² = 165221197 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165221209) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 506651 + ... + 506976.

It is an arithmetic number, because the mean of its divisors is an integer number (41558748).

Almost surely, 2^165221201 is an apocalyptic number.

It is an amenable number.

165221201 is a deficient number, since it is larger than the sum of its proper divisors (1013791).

165221201 is a wasteful number, since it uses less digits than its factorization.

165221201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1013790.

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 165221201 is about 12853.8399320981. The cubic root of 165221201 is about 548.7256457350.

Adding to 165221201 its reverse (102122561), we get a palindrome (267343762).

The spelling of 165221201 in words is "one hundred sixty-five million, two hundred twenty-one thousand, two hundred one".