1820689 has 4 divisors (see below), whose sum is σ = 1960756. Its totient is φ = 1680624.

The previous prime is 1820677. The next prime is 1820699. The reversal of 1820689 is 9860281.

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 380689 + 1440000 = 617^2 + 1200^2 .

It is a cyclic number.

It is not a de Polignac number, because 1820689 - 2¹⁷ = 1689617 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1820629) 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, 70014 + ... + 70039.

It is an arithmetic number, because the mean of its divisors is an integer number (490189).

2^1820689 is an apocalyptic number.

It is an amenable number.

1820689 is a deficient number, since it is larger than the sum of its proper divisors (140067).

1820689 is a wasteful number, since it uses less digits than its factorization.

1820689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140066.

The product of its (nonzero) digits is 6912, while the sum is 34.

The square root of 1820689 is about 1349.3290925493. The cubic root of 1820689 is about 122.1083199940.

The spelling of 1820689 in words is "one million, eight hundred twenty thousand, six hundred eighty-nine".