27919891 has 4 divisors (see below), whose sum is σ = 27954400. Its totient is φ = 27885384.

The previous prime is 27919889. The next prime is 27919897. The reversal of 27919891 is 19891972.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 27919891 - 2¹ = 27919889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (27919897) 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, 16011 + ... + 17668.

It is an arithmetic number, because the mean of its divisors is an integer number (6988600).

Almost surely, 2^27919891 is an apocalyptic number.

27919891 is a deficient number, since it is larger than the sum of its proper divisors (34509).

27919891 is an equidigital number, since it uses as much as digits as its factorization.

27919891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34508.

The product of its digits is 81648, while the sum is 46.

The square root of 27919891 is about 5283.9276111620. The cubic root of 27919891 is about 303.3690275859.

The spelling of 27919891 in words is "twenty-seven million, nine hundred nineteen thousand, eight hundred ninety-one".