1800989 has 4 divisors (see below), whose sum is σ = 1804860. Its totient is φ = 1797120.

The previous prime is 1800979. The next prime is 1801003. The reversal of 1800989 is 9890081.

It is a happy number.

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 708964 + 1092025 = 842^2 + 1045^2 .

It is a cyclic number.

It is not a de Polignac number, because 1800989 - 2⁴ = 1800973 is a prime.

It is a super-2 number, since 2×1800989² = 6487122756242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1800949) 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, 1124 + ... + 2205.

It is an arithmetic number, because the mean of its divisors is an integer number (451215).

2^1800989 is an apocalyptic number.

It is an amenable number.

1800989 is a deficient number, since it is larger than the sum of its proper divisors (3871).

1800989 is an equidigital number, since it uses as much as digits as its factorization.

1800989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3870.

The product of its (nonzero) digits is 5184, while the sum is 35.

The square root of 1800989 is about 1342.0093144237. The cubic root of 1800989 is about 121.6663147130. Note that the first 3 decimals are identical.

The spelling of 1800989 in words is "one million, eight hundred thousand, nine hundred eighty-nine".