1811899 has 2 divisors, whose sum is σ = 1811900. Its totient is φ = 1811898.

The previous prime is 1811893. The next prime is 1811903. The reversal of 1811899 is 9981181.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1811899 - 2⁵ = 1811867 is a prime.

It is not a weakly prime, because it can be changed into another prime (1811893) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 905949 + 905950.

It is an arithmetic number, because the mean of its divisors is an integer number (905950).

2^1811899 is an apocalyptic number.

1811899 is a deficient number, since it is larger than the sum of its proper divisors (1).

1811899 is an equidigital number, since it uses as much as digits as its factorization.

1811899 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5184, while the sum is 37.

The square root of 1811899 is about 1346.0679774811. The cubic root of 1811899 is about 121.9114963238.

It can be divided in two parts, 181 and 1899, that added together give a triangular number (2080 = T₆₄).

The spelling of 1811899 in words is "one million, eight hundred eleven thousand, eight hundred ninety-nine".