27978 has 8 divisors (see below), whose sum is σ = 55968. Its totient is φ = 9324.

The previous prime is 27967. The next prime is 27983. The reversal of 27978 is 87972.

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

27978 is an admirable number.

It is a nialpdrome in base 6 and base 13.

It is an unprimeable number.

27978 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2326 + ... + 2337.

It is an arithmetic number, because the mean of its divisors is an integer number (6996).

2²⁷⁹⁷⁸ is an apocalyptic number.

27978 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27984).

27978 is a wasteful number, since it uses less digits than its factorization.

27978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4668.

The product of its digits is 7056, while the sum is 33.

The square root of 27978 is about 167.2662548155. The cubic root of 27978 is about 30.3579346638.

The spelling of 27978 in words is "twenty-seven thousand, nine hundred seventy-eight".