1989605 has 4 divisors (see below), whose sum is σ = 2387532. Its totient is φ = 1591680.

The previous prime is 1989583. The next prime is 1989613. The reversal of 1989605 is 5069891.

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 872356 + 1117249 = 934^2 + 1057^2 .

It is not a de Polignac number, because 1989605 - 2¹² = 1985509 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 198956 + ... + 198965.

It is an arithmetic number, because the mean of its divisors is an integer number (596883).

2^1989605 is an apocalyptic number.

It is an amenable number.

1989605 is a deficient number, since it is larger than the sum of its proper divisors (397927).

1989605 is an equidigital number, since it uses as much as digits as its factorization.

1989605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 397926.

The product of its (nonzero) digits is 19440, while the sum is 38.

The square root of 1989605 is about 1410.5335869805. The cubic root of 1989605 is about 125.7734443994.

The spelling of 1989605 in words is "one million, nine hundred eighty-nine thousand, six hundred five".