27978820 has 24 divisors (see below), whose sum is σ = 58857624. Its totient is φ = 11172096.

The previous prime is 27978793. The next prime is 27978827. The reversal of 27978820 is 2887972.

It can be written as a sum of positive squares in 4 ways, for example, as 1784896 + 26193924 = 1336^2 + 5118^2 .

It is a hoax number, since the sum of its digits (43) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (27978827) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17994 + ... + 19486.

It is an arithmetic number, because the mean of its divisors is an integer number (2452401).

Almost surely, 2^27978820 is an apocalyptic number.

27978820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

27978820 is an abundant number, since it is smaller than the sum of its proper divisors (30878804).

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

27978820 is a wasteful number, since it uses less digits than its factorization.

27978820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2439 (or 2437 counting only the distinct ones).

The product of its (nonzero) digits is 112896, while the sum is 43.

The square root of 27978820 is about 5289.5009216371. The cubic root of 27978820 is about 303.5823124521.

The spelling of 27978820 in words is "twenty-seven million, nine hundred seventy-eight thousand, eight hundred twenty".