27998209 has 4 divisors (see below), whose sum is σ = 28017220. Its totient is φ = 27979200.

The previous prime is 27998197. The next prime is 27998249. The reversal of 27998209 is 90289972.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 23280625 + 4717584 = 4825^2 + 2172^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-27998209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (27998249) 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, 7092 + ... + 10309.

It is an arithmetic number, because the mean of its divisors is an integer number (7004305).

Almost surely, 2^27998209 is an apocalyptic number.

It is an amenable number.

27998209 is a deficient number, since it is larger than the sum of its proper divisors (19011).

27998209 is a wasteful number, since it uses less digits than its factorization.

27998209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19010.

The product of its (nonzero) digits is 163296, while the sum is 46.

The square root of 27998209 is about 5291.3333858301. Note that the first 4 decimals coincide. The cubic root of 27998209 is about 303.6524226080.

The spelling of 27998209 in words is "twenty-seven million, nine hundred ninety-eight thousand, two hundred nine".