55551 has 4 divisors (see below), whose sum is σ = 74072. Its totient is φ = 37032.

The previous prime is 55547. The next prime is 55579. The reversal of 55551 is 15555.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 55551 - 2² = 55547 is a prime.

It is a D-number.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55501) 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, 9256 + ... + 9261.

It is an arithmetic number, because the mean of its divisors is an integer number (18518).

2⁵⁵⁵⁵¹ is an apocalyptic number.

55551 is a deficient number, since it is larger than the sum of its proper divisors (18521).

55551 is a wasteful number, since it uses less digits than its factorization.

55551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18520.

The product of its digits is 625, while the sum is 21.

The square root of 55551 is about 235.6925964047. The cubic root of 55551 is about 38.1560984281.

It can be divided in two parts, 555 and 51, that added together give a palindrome (606).

The spelling of 55551 in words is "fifty-five thousand, five hundred fifty-one".