18827209 has 2 divisors, whose sum is σ = 18827210. Its totient is φ = 18827208.

The previous prime is 18827197. The next prime is 18827231. The reversal of 18827209 is 90272881.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14417209 + 4410000 = 3797^2 + 2100^2 .

It is an emirp because it is prime and its reverse (90272881) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18827209 - 2¹¹ = 18825161 is a prime.

It is not a weakly prime, because it can be changed into another prime (18827239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9413604 + 9413605.

It is an arithmetic number, because the mean of its divisors is an integer number (9413605).

Almost surely, 2^18827209 is an apocalyptic number.

It is an amenable number.

18827209 is a deficient number, since it is larger than the sum of its proper divisors (1).

18827209 is an equidigital number, since it uses as much as digits as its factorization.

18827209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 18827209 is about 4339.0331872434. The cubic root of 18827209 is about 266.0287953827.

The spelling of 18827209 in words is "eighteen million, eight hundred twenty-seven thousand, two hundred nine".