813520 has 20 divisors (see below), whose sum is σ = 1891620. Its totient is φ = 325376.

The previous prime is 813511. The next prime is 813529. The reversal of 813520 is 25318.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (813511) and next prime (813529).

It can be written as a sum of positive squares in 2 ways, for example, as 559504 + 254016 = 748^2 + 504^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (813529) 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, 5005 + ... + 5164.

It is an arithmetic number, because the mean of its divisors is an integer number (94581).

2⁸¹³⁵²⁰ is an apocalyptic number.

813520 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

813520 is an abundant number, since it is smaller than the sum of its proper divisors (1078100).

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

813520 is a wasteful number, since it uses less digits than its factorization.

813520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10182 (or 10176 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 813520 is about 901.9534356052. The cubic root of 813520 is about 93.3518104008.

Adding to 813520 its reverse (25318), we get a palindrome (838838).

The spelling of 813520 in words is "eight hundred thirteen thousand, five hundred twenty".