810020 has 24 divisors (see below), whose sum is σ = 1722168. Its totient is φ = 320000.

The previous prime is 810013. The next prime is 810023. The reversal of 810020 is 20018.

810020 = T₄₄₆ + T₄₄₇ + ... + T₄₅₃.

810020 = 15² + 16² + ... + 134².

It can be written as a sum of positive squares in 4 ways, for example, as 541696 + 268324 = 736^2 + 518^2 .

It is a super-2 number, since 2×810020² = 1312264800800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 809983 and 810010.

It is not an unprimeable number, because it can be changed into a prime (810023) by changing a digit.

810020 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1820 + ... + 2220.

It is an arithmetic number, because the mean of its divisors is an integer number (71757).

2⁸¹⁰⁰²⁰ is an apocalyptic number.

It is an amenable number.

810020 is an abundant number, since it is smaller than the sum of its proper divisors (912148).

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

810020 is a wasteful number, since it uses less digits than its factorization.

810020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 511 (or 509 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 810020 is about 900.0111110425. The cubic root of 810020 is about 93.2177423902.

Adding to 810020 its reverse (20018), we get a palindrome (830038).

The spelling of 810020 in words is "eight hundred ten thousand, twenty".