815381 has 4 divisors (see below), whose sum is σ = 931872. Its totient is φ = 698892.

The previous prime is 815351. The next prime is 815389. The reversal of 815381 is 183518.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 815381 - 2⁶ = 815317 is a prime.

It is a super-2 number, since 2×815381² = 1329692350322, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 815381.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (815389) 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, 58235 + ... + 58248.

It is an arithmetic number, because the mean of its divisors is an integer number (232968).

2⁸¹⁵³⁸¹ is an apocalyptic number.

It is an amenable number.

815381 is a deficient number, since it is larger than the sum of its proper divisors (116491).

815381 is a wasteful number, since it uses less digits than its factorization.

815381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116490.

The product of its digits is 960, while the sum is 26.

The square root of 815381 is about 902.9844959909. The cubic root of 815381 is about 93.4229397378.

Adding to 815381 its reverse (183518), we get a palindrome (998899).

The spelling of 815381 in words is "eight hundred fifteen thousand, three hundred eighty-one".