27990181 has 4 divisors (see below), whose sum is σ = 28001164. Its totient is φ = 27979200.

The previous prime is 27990169. The next prime is 27990187. The reversal of 27990181 is 18109972.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 10692900 + 17297281 = 3270^2 + 4159^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-27990181 is a prime.

It is a super-2 number, since 2×27990181² = 1566900464825522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 27990181.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27990187) 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, 541 + ... + 7501.

It is an arithmetic number, because the mean of its divisors is an integer number (7000291).

Almost surely, 2^27990181 is an apocalyptic number.

It is an amenable number.

27990181 is a deficient number, since it is larger than the sum of its proper divisors (10983).

27990181 is an equidigital number, since it uses as much as digits as its factorization.

27990181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10982.

The product of its (nonzero) digits is 9072, while the sum is 37.

The square root of 27990181 is about 5290.5747324842. The cubic root of 27990181 is about 303.6233974815.

The spelling of 27990181 in words is "twenty-seven million, nine hundred ninety thousand, one hundred eighty-one".