851820 has 24 divisors (see below), whose sum is σ = 2385264. Its totient is φ = 227136.

The previous prime is 851813. The next prime is 851821. The reversal of 851820 is 28158.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 851820.

It is not an unprimeable number, because it can be changed into a prime (851821) 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, 7039 + ... + 7158.

It is an arithmetic number, because the mean of its divisors is an integer number (99386).

2⁸⁵¹⁸²⁰ is an apocalyptic number.

It is an amenable number.

851820 is an abundant number, since it is smaller than the sum of its proper divisors (1533444).

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

851820 is a wasteful number, since it uses less digits than its factorization.

851820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14209 (or 14207 counting only the distinct ones).

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

The square root of 851820 is about 922.9409515240. The cubic root of 851820 is about 94.7943844704.

Adding to 851820 its reverse (28158), we get a palindrome (879978).

The spelling of 851820 in words is "eight hundred fifty-one thousand, eight hundred twenty".