551820 has 48 divisors (see below), whose sum is σ = 1639008. Its totient is φ = 138240.

The previous prime is 551813. The next prime is 551843. The reversal of 551820 is 28155.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 750 + ... + 1290.

It is an arithmetic number, because the mean of its divisors is an integer number (34146).

2⁵⁵¹⁸²⁰ 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 551820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (819504).

551820 is an abundant number, since it is smaller than the sum of its proper divisors (1087188).

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

551820 is a wasteful number, since it uses less digits than its factorization.

551820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 570 (or 568 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 21.

The square root of 551820 is about 742.8458790355. The cubic root of 551820 is about 82.0224011770.

Adding to 551820 its reverse (28155), we get a palindrome (579975).

The spelling of 551820 in words is "five hundred fifty-one thousand, eight hundred twenty".