1808993 has 2 divisors, whose sum is σ = 1808994. Its totient is φ = 1808992.

The previous prime is 1808981. The next prime is 1809029. The reversal of 1808993 is 3998081.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1420864 + 388129 = 1192^2 + 623^2 .

It is a cyclic number.

It is not a de Polignac number, because 1808993 - 2⁴ = 1808977 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1808923) 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 as a sum of consecutive naturals, namely, 904496 + 904497.

It is an arithmetic number, because the mean of its divisors is an integer number (904497).

2^1808993 is an apocalyptic number.

It is an amenable number.

1808993 is a deficient number, since it is larger than the sum of its proper divisors (1).

1808993 is an equidigital number, since it uses as much as digits as its factorization.

1808993 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15552, while the sum is 38.

The square root of 1808993 is about 1344.9881040366. The cubic root of 1808993 is about 121.8462858499.

The spelling of 1808993 in words is "one million, eight hundred eight thousand, nine hundred ninety-three".