813819 has 4 divisors (see below), whose sum is σ = 1085096. Its totient is φ = 542544.

The previous prime is 813817. The next prime is 813829. The reversal of 813819 is 918318.

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

It is not a de Polignac number, because 813819 - 2¹ = 813817 is a prime.

It is a super-2 number, since 2×813819² = 1324602729522, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (813811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 135634 + ... + 135639.

It is an arithmetic number, because the mean of its divisors is an integer number (271274).

2⁸¹³⁸¹⁹ is an apocalyptic number.

813819 is a deficient number, since it is larger than the sum of its proper divisors (271277).

813819 is a wasteful number, since it uses less digits than its factorization.

813819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 271276.

The product of its digits is 1728, while the sum is 30.

The square root of 813819 is about 902.1191717284. The cubic root of 813819 is about 93.3632457978.

The spelling of 813819 in words is "eight hundred thirteen thousand, eight hundred nineteen".