It is a sphenic number, since it is the product of 3 distinct primes.
It is a 5-Lehmer number, since φ(5551) divides (5551-1)5.
It is a cyclic number.
It is the 75-th Hogben number.
5551 is a lucky number.
It is a plaindrome in base 4 and base 16.
It is a nialpdrome in base 10.
It is a zygodrome in base 4.
It is a congruent number.
25551 is an apocalyptic number.
5551 is the 61-st pentagonal number.
5551 is a wasteful number, since it uses less digits than its factorization.
5551 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 81.
The square root of 5551 is about 74.5050333870. The cubic root of 5551 is about 17.7061338291.
The spelling of 5551 in words is "five thousand, five hundred fifty-one".