1819 has 4 divisors (see below), whose sum is σ = 1944. Its totient is φ = 1696.

The previous prime is 1811. The next prime is 1823. The reversal of 1819 is 9181.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1819 - 2³ = 1811 is a prime.

It is a super-2 number, since 2×1819² = 6617522, which contains 22 as substring.

It is a Duffinian number.

1819 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 1796 and 1805.

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 (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 37 + ... + 70.

It is an arithmetic number, because the mean of its divisors is an integer number (486).

2¹⁸¹⁹ is an apocalyptic number.

1819 is a deficient number, since it is larger than the sum of its proper divisors (125).

1819 is a wasteful number, since it uses less digits than its factorization.

1819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124.

The product of its digits is 72, while the sum is 19.

The square root of 1819 is about 42.6497362243. The cubic root of 1819 is about 12.2070549538.

Adding to 1819 its product of digits (72), we get a triangular number (1891 = T₆₁).

It can be divided in two parts, 181 and 9, that added together give a triangular number (190 = T₁₉).

The spelling of 1819 in words is "one thousand, eight hundred nineteen".