551781 has 12 divisors (see below), whose sum is σ = 819052. Its totient is φ = 357696.

The previous prime is 551773. The next prime is 551801. The reversal of 551781 is 187155.

551781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 349281 + 202500 = 591^2 + 450^2 .

It is not a de Polignac number, because 551781 - 2³ = 551773 is a prime.

It is a super-2 number, since 2×551781² = 608924543922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (551731) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 496 + ... + 1161.

2⁵⁵¹⁷⁸¹ is an apocalyptic number.

It is an amenable number.

551781 is a deficient number, since it is larger than the sum of its proper divisors (267271).

551781 is a wasteful number, since it uses less digits than its factorization.

551781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1700 (or 1697 counting only the distinct ones).

The product of its digits is 1400, while the sum is 27.

The square root of 551781 is about 742.8196281736. The cubic root of 551781 is about 82.0204688144.

The spelling of 551781 in words is "five hundred fifty-one thousand, seven hundred eighty-one".