5551 has 8 divisors (see below), whose sum is σ = 6944. Its totient is φ = 4320.

The previous prime is 5531. The next prime is 5557. The reversal of 5551 is 1555.

5551 = 13² + 14² + ... + 26².

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 not a de Polignac number, because 5551 - 2⁵ = 5519 is a prime.

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.

It is not an unprimeable number, because it can be changed into a prime (5557) by changing a digit.

It is a nontrivial repunit in base 74.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 61 + ... + 121.

It is an arithmetic number, because the mean of its divisors is an integer number (868).

2⁵⁵⁵¹ is an apocalyptic number.

5551 is the 61-st pentagonal number.

5551 is a deficient number, since it is larger than the sum of its proper divisors (1393).

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 product of its digits is 125, while the sum is 16.

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".