27856221 has 4 divisors (see below), whose sum is σ = 37141632. Its totient is φ = 18570812.

The previous prime is 27856207. The next prime is 27856229. The reversal of 27856221 is 12265872.

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 27856221 - 2¹⁷ = 27725149 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27856229) 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, 4642701 + ... + 4642706.

It is an arithmetic number, because the mean of its divisors is an integer number (9285408).

Almost surely, 2^27856221 is an apocalyptic number.

It is an amenable number.

27856221 is a deficient number, since it is larger than the sum of its proper divisors (9285411).

27856221 is an equidigital number, since it uses as much as digits as its factorization.

27856221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9285410.

The product of its digits is 13440, while the sum is 33.

The square root of 27856221 is about 5277.8992980162. The cubic root of 27856221 is about 303.1382457952.

The spelling of 27856221 in words is "twenty-seven million, eight hundred fifty-six thousand, two hundred twenty-one".