551987 has 4 divisors (see below), whose sum is σ = 553536. Its totient is φ = 550440.

The previous prime is 551981. The next prime is 552001. The reversal of 551987 is 789155.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 789155 = 5 ⋅157831.

It is a cyclic number.

It is not a de Polignac number, because 551987 - 2⁸ = 551731 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (551981) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 62 + ... + 1052.

It is an arithmetic number, because the mean of its divisors is an integer number (138384).

2⁵⁵¹⁹⁸⁷ is an apocalyptic number.

551987 is a deficient number, since it is larger than the sum of its proper divisors (1549).

551987 is an equidigital number, since it uses as much as digits as its factorization.

551987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1548.

The product of its digits is 12600, while the sum is 35.

The square root of 551987 is about 742.9582760828. The cubic root of 551987 is about 82.0306746233.

The spelling of 551987 in words is "five hundred fifty-one thousand, nine hundred eighty-seven".