815383813 has 4 divisors (see below), whose sum is σ = 815466988. Its totient is φ = 815300640.

The previous prime is 815383753. The next prime is 815383861. The reversal of 815383813 is 318383518.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 61496964 + 753886849 = 7842^2 + 27457^2 .

It is a cyclic number.

It is not a de Polignac number, because 815383813 - 2¹³ = 815375621 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (815383883) 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, 24558 + ... + 47263.

It is an arithmetic number, because the mean of its divisors is an integer number (203866747).

Almost surely, 2^815383813 is an apocalyptic number.

It is an amenable number.

815383813 is a deficient number, since it is larger than the sum of its proper divisors (83175).

815383813 is a wasteful number, since it uses less digits than its factorization.

815383813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83174.

The product of its digits is 69120, while the sum is 40.

The square root of 815383813 is about 28554.9262474971. The cubic root of 815383813 is about 934.2304717162.

The spelling of 815383813 in words is "eight hundred fifteen million, three hundred eighty-three thousand, eight hundred thirteen".