55191 has 4 divisors (see below), whose sum is σ = 73592. Its totient is φ = 36792.

The previous prime is 55171. The next prime is 55201. The reversal of 55191 is 19155.

It is a happy number.

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

It is not a de Polignac number, because 55191 - 2⁶ = 55127 is a prime.

It is a D-number.

It is a Duffinian number.

55191 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9196 + ... + 9201.

It is an arithmetic number, because the mean of its divisors is an integer number (18398).

2⁵⁵¹⁹¹ is an apocalyptic number.

55191 is a deficient number, since it is larger than the sum of its proper divisors (18401).

55191 is a wasteful number, since it uses less digits than its factorization.

55191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18400.

The product of its digits is 225, while the sum is 21.

The square root of 55191 is about 234.9276484367. The cubic root of 55191 is about 38.0734958026.

The spelling of 55191 in words is "fifty-five thousand, one hundred ninety-one".