815540 has 36 divisors (see below), whose sum is σ = 1888068. Its totient is φ = 295680.

The previous prime is 815539. The next prime is 815543. The reversal of 815540 is 45518.

815540 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 2 ways, for example, as 256036 + 559504 = 506^2 + 748^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (815543) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2252 + ... + 2588.

2⁸¹⁵⁵⁴⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 815540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (944034).

815540 is an abundant number, since it is smaller than the sum of its proper divisors (1072528).

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

815540 is a wasteful number, since it uses less digits than its factorization.

815540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 368 (or 355 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 23.

The square root of 815540 is about 903.0725330780. The cubic root of 815540 is about 93.4290118612.

The spelling of 815540 in words is "eight hundred fifteen thousand, five hundred forty".