815820 has 24 divisors (see below), whose sum is σ = 2284464. Its totient is φ = 217536.

The previous prime is 815819. The next prime is 815821. The reversal of 815820 is 28518.

815820 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (815819) and next prime (815821).

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 7 ways as a sum of consecutive naturals, for example, 6739 + ... + 6858.

It is an arithmetic number, because the mean of its divisors is an integer number (95186).

2⁸¹⁵⁸²⁰ is an apocalyptic number.

It is an amenable number.

815820 is an abundant number, since it is smaller than the sum of its proper divisors (1468644).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

815820 is a wasteful number, since it uses less digits than its factorization.

815820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13609 (or 13607 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 24.

The square root of 815820 is about 903.2275460813. The cubic root of 815820 is about 93.4397029902.

The spelling of 815820 in words is "eight hundred fifteen thousand, eight hundred twenty".