27931891 has 4 divisors (see below), whose sum is σ = 30080512. Its totient is φ = 25783272.

The previous prime is 27931873. The next prime is 27931909. The reversal of 27931891 is 19813972.

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

It is an interprime number because it is at equal distance from previous prime (27931873) and next prime (27931909).

It is a cyclic number.

It is not a de Polignac number, because 27931891 - 2⁵ = 27931859 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (27931801) 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, 1074291 + ... + 1074316.

It is an arithmetic number, because the mean of its divisors is an integer number (7520128).

Almost surely, 2^27931891 is an apocalyptic number.

27931891 is a deficient number, since it is larger than the sum of its proper divisors (2148621).

27931891 is a wasteful number, since it uses less digits than its factorization.

27931891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2148620.

The product of its digits is 27216, while the sum is 40.

The square root of 27931891 is about 5285.0630081391. The cubic root of 27931891 is about 303.4124841416.

The spelling of 27931891 in words is "twenty-seven million, nine hundred thirty-one thousand, eight hundred ninety-one".