551720 has 32 divisors (see below), whose sum is σ = 1338120. Its totient is φ = 203520.

The previous prime is 551717. The next prime is 551723. The reversal of 551720 is 27155.

It is an interprime number because it is at equal distance from previous prime (551717) and next prime (551723).

It can be written as a sum of positive squares in 4 ways, for example, as 386884 + 164836 = 622^2 + 406^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 551692 and 551701.

It is not an unprimeable number, because it can be changed into a prime (551723) 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, 11 + ... + 1050.

2⁵⁵¹⁷²⁰ 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 551720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (669060).

551720 is an abundant number, since it is smaller than the sum of its proper divisors (786400).

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

551720 is a wasteful number, since it uses less digits than its factorization.

551720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1085 (or 1081 counting only the distinct ones).

The product of its (nonzero) digits is 350, while the sum is 20.

The square root of 551720 is about 742.7785672729. The cubic root of 551720 is about 82.0174462185.

Adding to 551720 its reverse (27155), we get a palindrome (578875).

The spelling of 551720 in words is "five hundred fifty-one thousand, seven hundred twenty".