201819 has 4 divisors (see below), whose sum is σ = 269096. Its totient is φ = 134544.

The previous prime is 201809. The next prime is 201821. The reversal of 201819 is 918102.

201819 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 201819 - 2⁵ = 201787 is a prime.

It is a super-2 number, since 2×201819² = 81461817522, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 201795 and 201804.

It is not an unprimeable number, because it can be changed into a prime (201809) 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, 33634 + ... + 33639.

It is an arithmetic number, because the mean of its divisors is an integer number (67274).

2²⁰¹⁸¹⁹ is an apocalyptic number.

201819 is a deficient number, since it is larger than the sum of its proper divisors (67277).

201819 is an equidigital number, since it uses as much as digits as its factorization.

201819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67276.

The product of its (nonzero) digits is 144, while the sum is 21.

The square root of 201819 is about 449.2426961009. The cubic root of 201819 is about 58.6571129128.

The spelling of 201819 in words is "two hundred one thousand, eight hundred nineteen".