815825 has 6 divisors (see below), whose sum is σ = 1011654. Its totient is φ = 652640.

The previous prime is 815821. The next prime is 815831. The reversal of 815825 is 528518.

815825 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 3 ways, for example, as 96721 + 719104 = 311^2 + 848^2 .

It is not a de Polignac number, because 815825 - 2² = 815821 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 (815821) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 16292 + ... + 16341.

It is an arithmetic number, because the mean of its divisors is an integer number (168609).

2⁸¹⁵⁸²⁵ is an apocalyptic number.

It is an amenable number.

815825 is a deficient number, since it is larger than the sum of its proper divisors (195829).

815825 is a wasteful number, since it uses less digits than its factorization.

815825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32643 (or 32638 counting only the distinct ones).

The product of its digits is 3200, while the sum is 29.

The square root of 815825 is about 903.2303139288. The cubic root of 815825 is about 93.4398938809.

Adding to 815825 its product of digits (3200), we get a square (819025 = 905²).

The spelling of 815825 in words is "eight hundred fifteen thousand, eight hundred twenty-five".