27978591 has 8 divisors (see below), whose sum is σ = 38591280. Its totient is φ = 18009152.

The previous prime is 27978581. The next prime is 27978593. The reversal of 27978591 is 19587972.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 27978591 - 2¹³ = 27970399 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 27978591.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27978593) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 160710 + ... + 160883.

It is an arithmetic number, because the mean of its divisors is an integer number (4823910).

Almost surely, 2^27978591 is an apocalyptic number.

27978591 is a deficient number, since it is larger than the sum of its proper divisors (10612689).

27978591 is a wasteful number, since it uses less digits than its factorization.

27978591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 321625.

The product of its digits is 317520, while the sum is 48.

The square root of 27978591 is about 5289.4792749381. The cubic root of 27978591 is about 303.5814842001.

The spelling of 27978591 in words is "twenty-seven million, nine hundred seventy-eight thousand, five hundred ninety-one".