1805989 has 2 divisors, whose sum is σ = 1805990. Its totient is φ = 1805988.

The previous prime is 1805963. The next prime is 1806001. The reversal of 1805989 is 9895081.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1481089 + 324900 = 1217^2 + 570^2 .

It is a cyclic number.

It is not a de Polignac number, because 1805989 - 2¹⁷ = 1674917 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1805789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 902994 + 902995.

It is an arithmetic number, because the mean of its divisors is an integer number (902995).

2^1805989 is an apocalyptic number.

It is an amenable number.

1805989 is a deficient number, since it is larger than the sum of its proper divisors (1).

1805989 is an equidigital number, since it uses as much as digits as its factorization.

1805989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25920, while the sum is 40.

The square root of 1805989 is about 1343.8709015378. The cubic root of 1805989 is about 121.7788028107.

The spelling of 1805989 in words is "one million, eight hundred five thousand, nine hundred eighty-nine".