28166181 has 16 divisors (see below), whose sum is σ = 38252928. Its totient is φ = 18432000.

The previous prime is 28166167. The next prime is 28166209. The reversal of 28166181 is 18166182.

It is not a de Polignac number, because 28166181 - 2¹⁰ = 28165157 is a prime.

It is a super-2 number, since 2×28166181² = 1586667504249522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28166081) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 43621 + ... + 44261.

It is an arithmetic number, because the mean of its divisors is an integer number (2390808).

Almost surely, 2^28166181 is an apocalyptic number.

It is an amenable number.

28166181 is a deficient number, since it is larger than the sum of its proper divisors (10086747).

28166181 is a wasteful number, since it uses less digits than its factorization.

28166181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 892.

The product of its digits is 4608, while the sum is 33.

The square root of 28166181 is about 5307.1820206207. The cubic root of 28166181 is about 304.2584547487.

Subtracting from 28166181 its reverse (18166182), we obtain a palindrome (9999999).

The spelling of 28166181 in words is "twenty-eight million, one hundred sixty-six thousand, one hundred eighty-one".