1812 has 12 divisors (see below), whose sum is σ = 4256. Its totient is φ = 600.

The previous prime is 1811. The next prime is 1823. The reversal of 1812 is 2181.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (12).

It is a hoax number, since the sum of its digits (12) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (12), and also a Moran number because the ratio is a prime number: 151 = 1812 / (1 + 8 + 1 + 2).

It is an Ulam number.

It is an alternating number because its digits alternate between odd and even.

It is a nialpdrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64 + ... + 87.

2¹⁸¹² is an apocalyptic number.

1812 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1812 is an abundant number, since it is smaller than the sum of its proper divisors (2444).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2128).

1812 is a wasteful number, since it uses less digits than its factorization.

1812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158 (or 156 counting only the distinct ones).

The product of its digits is 16, while the sum is 12.

The square root of 1812 is about 42.5675933076. The cubic root of 1812 is about 12.1913761504.

1812 divided by its sum of digits (12) gives a palindrome (151).

Adding to 1812 its reverse (2181), we get a palindrome (3993).

It can be divided in two parts, 18 and 12, that multiplied together give a cube (216 = 6³).

The spelling of 1812 in words is "one thousand, eight hundred twelve".