1989209 has 4 divisors (see below), whose sum is σ = 1994916. Its totient is φ = 1983504.

The previous prime is 1989203. The next prime is 1989217. The reversal of 1989209 is 9029891.

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 1690000 + 299209 = 1300^2 + 547^2 .

It is a cyclic number.

It is not a de Polignac number, because 1989209 - 2⁴ = 1989193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1989203) 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, 2294 + ... + 3039.

It is an arithmetic number, because the mean of its divisors is an integer number (498729).

2^1989209 is an apocalyptic number.

It is an amenable number.

1989209 is a deficient number, since it is larger than the sum of its proper divisors (5707).

1989209 is an equidigital number, since it uses as much as digits as its factorization.

1989209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5706.

The product of its (nonzero) digits is 11664, while the sum is 38.

The square root of 1989209 is about 1410.3932075843. The cubic root of 1989209 is about 125.7650994283.

The spelling of 1989209 in words is "one million, nine hundred eighty-nine thousand, two hundred nine".