813220 has 24 divisors (see below), whose sum is σ = 1734264. Its totient is φ = 320256.

The previous prime is 813217. The next prime is 813221. The reversal of 813220 is 22318.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 10404 + 802816 = 102^2 + 896^2 .

It is a super-2 number, since 2×813220² = 1322653536800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 813194 and 813203.

It is not an unprimeable number, because it can be changed into a prime (813221) 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, 1182 + ... + 1738.

It is an arithmetic number, because the mean of its divisors is an integer number (72261).

2⁸¹³²²⁰ is an apocalyptic number.

It is an amenable number.

813220 is an abundant number, since it is smaller than the sum of its proper divisors (921044).

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

813220 is a wasteful number, since it uses less digits than its factorization.

813220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 639 (or 637 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 813220 is about 901.7871145675. The cubic root of 813220 is about 93.3403339420.

Adding to 813220 its reverse (22318), we get a palindrome (835538).

The spelling of 813220 in words is "eight hundred thirteen thousand, two hundred twenty".