28185181 has 2 divisors, whose sum is σ = 28185182. Its totient is φ = 28185180.

The previous prime is 28185137. The next prime is 28185197. The reversal of 28185181 is 18158182.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25908100 + 2277081 = 5090^2 + 1509^2 .

It is a cyclic number.

It is not a de Polignac number, because 28185181 - 2⁹ = 28184669 is a prime.

It is a super-2 number, since 2×28185181² = 1588808856005522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28185121) 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 as a sum of consecutive naturals, namely, 14092590 + 14092591.

It is an arithmetic number, because the mean of its divisors is an integer number (14092591).

Almost surely, 2^28185181 is an apocalyptic number.

It is an amenable number.

28185181 is a deficient number, since it is larger than the sum of its proper divisors (1).

28185181 is an equidigital number, since it uses as much as digits as its factorization.

28185181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5120, while the sum is 34.

The square root of 28185181 is about 5308.9717460164. The cubic root of 28185181 is about 304.3268536944.

The spelling of 28185181 in words is "twenty-eight million, one hundred eighty-five thousand, one hundred eighty-one".