813919 has 4 divisors (see below), whose sum is σ = 817344. Its totient is φ = 810496.

The previous prime is 813907. The next prime is 813931. The reversal of 813919 is 919318.

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

It is an interprime number because it is at equal distance from previous prime (813907) and next prime (813931).

It is a cyclic number.

It is not a de Polignac number, because 813919 - 2¹¹ = 811871 is a prime.

It is a super-2 number, since 2×813919² = 1324928277122, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (813419) 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, 1327 + ... + 1840.

It is an arithmetic number, because the mean of its divisors is an integer number (204336).

2⁸¹³⁹¹⁹ is an apocalyptic number.

813919 is a deficient number, since it is larger than the sum of its proper divisors (3425).

813919 is a wasteful number, since it uses less digits than its factorization.

813919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3424.

The product of its digits is 1944, while the sum is 31.

The square root of 813919 is about 902.1745950757. The cubic root of 813919 is about 93.3670697202.

The spelling of 813919 in words is "eight hundred thirteen thousand, nine hundred nineteen".