1989609 has 4 divisors (see below), whose sum is σ = 2652816. Its totient is φ = 1326404.

The previous prime is 1989583. The next prime is 1989613. The reversal of 1989609 is 9069891.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1989609 - 2⁸ = 1989353 is a prime.

It is a D-number.

It is a Curzon number.

1989609 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1989619) 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, 331599 + ... + 331604.

It is an arithmetic number, because the mean of its divisors is an integer number (663204).

2^1989609 is an apocalyptic number.

It is an amenable number.

1989609 is a deficient number, since it is larger than the sum of its proper divisors (663207).

1989609 is an equidigital number, since it uses as much as digits as its factorization.

1989609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 663206.

The product of its (nonzero) digits is 34992, while the sum is 42.

The square root of 1989609 is about 1410.5350048829. The cubic root of 1989609 is about 125.7735286864.

The spelling of 1989609 in words is "one million, nine hundred eighty-nine thousand, six hundred nine".