1800813 has 16 divisors (see below), whose sum is σ = 2839680. Its totient is φ = 993216.

The previous prime is 1800811. The next prime is 1800823. The reversal of 1800813 is 3180081.

It is a happy number.

It is not a de Polignac number, because 1800813 - 2¹ = 1800811 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

1800813 is a modest number, since divided by 813 gives 18 as remainder.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1800813.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1800811) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 870 + ... + 2087.

It is an arithmetic number, because the mean of its divisors is an integer number (177480).

2^1800813 is an apocalyptic number.

It is an amenable number.

1800813 is a deficient number, since it is larger than the sum of its proper divisors (1038867).

1800813 is a wasteful number, since it uses less digits than its factorization.

1800813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2996.

The product of its (nonzero) digits is 192, while the sum is 21.

The square root of 1800813 is about 1341.9437395062. The cubic root of 1800813 is about 121.6623513409.

Adding to 1800813 its reverse (3180081), we get a palindrome (4980894).

The spelling of 1800813 in words is "one million, eight hundred thousand, eight hundred thirteen".