27978666 has 8 divisors (see below), whose sum is σ = 55957344. Its totient is φ = 9326220.

The previous prime is 27978661. The next prime is 27978701. The reversal of 27978666 is 66687972.

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

27978666 is an admirable number.

It is a super-2 number, since 2×27978666² = 1565611502279112, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (27978661) 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, 2331550 + ... + 2331561.

It is an arithmetic number, because the mean of its divisors is an integer number (6994668).

Almost surely, 2^27978666 is an apocalyptic number.

27978666 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.

27978666 is a wasteful number, since it uses less digits than its factorization.

27978666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4663116.

The product of its digits is 1524096, while the sum is 51.

The square root of 27978666 is about 5289.4863644781. The cubic root of 27978666 is about 303.5817554622.

The spelling of 27978666 in words is "twenty-seven million, nine hundred seventy-eight thousand, six hundred sixty-six".