1811813 has 4 divisors (see below), whose sum is σ = 1815360. Its totient is φ = 1808268.

The previous prime is 1811791. The next prime is 1811819. The reversal of 1811813 is 3181181.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1811813 - 2²⁰ = 763237 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1811819) 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, 845 + ... + 2082.

It is an arithmetic number, because the mean of its divisors is an integer number (453840).

2^1811813 is an apocalyptic number.

It is an amenable number.

1811813 is a deficient number, since it is larger than the sum of its proper divisors (3547).

1811813 is an equidigital number, since it uses as much as digits as its factorization.

1811813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3546.

The product of its digits is 192, while the sum is 23.

The square root of 1811813 is about 1346.0360322072. The cubic root of 1811813 is about 121.9095674903.

Adding to 1811813 its reverse (3181181), we get a palindrome (4992994).

The spelling of 1811813 in words is "one million, eight hundred eleven thousand, eight hundred thirteen".