27840 has 56 divisors (see below), whose sum is σ = 91440. Its totient is φ = 7168.

The previous prime is 27827. The next prime is 27847. The reversal of 27840 is 4872.

It is a happy number.

It is a hoax number, since the sum of its digits (21) coincides with the sum of the digits of its distinct prime factors.

It is a nialpdrome in base 8.

It is not an unprimeable number, because it can be changed into a prime (27847) by changing a digit.

27840 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 7 ways as a sum of consecutive naturals, for example, 946 + ... + 974.

2²⁷⁸⁴⁰ is an apocalyptic number.

27840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 27840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45720).

27840 is an abundant number, since it is smaller than the sum of its proper divisors (63600).

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

27840 is a wasteful number, since it uses less digits than its factorization.

27840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49 (or 39 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 21.

The square root of 27840 is about 166.8532289169. The cubic root of 27840 is about 30.3079394067.

The spelling of 27840 in words is "twenty-seven thousand, eight hundred forty".