1989645 has 24 divisors (see below), whose sum is σ = 3704544. Its totient is φ = 909216.

The previous prime is 1989643. The next prime is 1989671. The reversal of 1989645 is 5469891.

It is not a de Polignac number, because 1989645 - 2¹ = 1989643 is a prime.

It is a super-3 number, since 3×1989645³ = 23629146737473533375, which contains 333 as substring.

1989645 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 1989597 and 1989606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1989643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 619 + ... + 2088.

It is an arithmetic number, because the mean of its divisors is an integer number (154356).

2^1989645 is an apocalyptic number.

1989645 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1989645 is a deficient number, since it is larger than the sum of its proper divisors (1714899).

1989645 is a wasteful number, since it uses less digits than its factorization.

1989645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2729 (or 2722 counting only the distinct ones).

The product of its digits is 77760, while the sum is 42.

The square root of 1989645 is about 1410.5477659406. The cubic root of 1989645 is about 125.7742872642.

The spelling of 1989645 in words is "one million, nine hundred eighty-nine thousand, six hundred forty-five".