551540 has 48 divisors (see below), whose sum is σ = 1330560. Its totient is φ = 190080.

The previous prime is 551539. The next prime is 551543. The reversal of 551540 is 45155.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (551543) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5006 + ... + 5114.

It is an arithmetic number, because the mean of its divisors is an integer number (27720).

2⁵⁵¹⁵⁴⁰ 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 551540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (665280).

551540 is an abundant number, since it is smaller than the sum of its proper divisors (779020).

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

551540 is a wasteful number, since it uses less digits than its factorization.

551540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 152 (or 150 counting only the distinct ones).

The product of its (nonzero) digits is 500, while the sum is 20.

The square root of 551540 is about 742.6573907260. The cubic root of 551540 is about 82.0085257842.

Adding to 551540 its reverse (45155), we get a palindrome (596695).

It can be divided in two parts, 5515 and 40, that added together give a palindrome (5555).

The spelling of 551540 in words is "five hundred fifty-one thousand, five hundred forty".