166027221 has 6 divisors (see below), whose sum is σ = 239817110. Its totient is φ = 110684808.

The previous prime is 166027207. The next prime is 166027229. The reversal of 166027221 is 122720661.

It can be written as a sum of positive squares in only one way, i.e., 132503121 + 33524100 = 11511^2 + 5790^2 .

It is not a de Polignac number, because 166027221 - 2⁵ = 166027189 is a prime.

It is a super-2 number, since 2×166027221² = 55130076225965682, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166027229) 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, 9223726 + ... + 9223743.

Almost surely, 2^166027221 is an apocalyptic number.

It is an amenable number.

166027221 is a deficient number, since it is larger than the sum of its proper divisors (73789889).

166027221 is a wasteful number, since it uses less digits than its factorization.

166027221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18447475 (or 18447472 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 166027221 is about 12885.1550630949. The cubic root of 166027221 is about 549.6165051170.

Adding to 166027221 its reverse (122720661), we get a palindrome (288747882).

The spelling of 166027221 in words is "one hundred sixty-six million, twenty-seven thousand, two hundred twenty-one".