813993 has 16 divisors (see below), whose sum is σ = 1161216. Its totient is φ = 506000.

The previous prime is 813991. The next prime is 813997. The reversal of 813993 is 399318.

It is not a de Polignac number, because 813993 - 2¹ = 813991 is a prime.

Its product of digits (5832) is a multiple of the sum of its prime divisors (324).

It is a plaindrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (813991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3118 + ... + 3368.

It is an arithmetic number, because the mean of its divisors is an integer number (72576).

2⁸¹³⁹⁹³ is an apocalyptic number.

It is an amenable number.

813993 is a deficient number, since it is larger than the sum of its proper divisors (347223).

813993 is a wasteful number, since it uses less digits than its factorization.

813993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 324.

The product of its digits is 5832, while the sum is 33.

The square root of 813993 is about 902.2156061607. The cubic root of 813993 is about 93.3698992212.

The spelling of 813993 in words is "eight hundred thirteen thousand, nine hundred ninety-three".