55911 has 4 divisors (see below), whose sum is σ = 74552. Its totient is φ = 37272.

The previous prime is 55903. The next prime is 55921. The reversal of 55911 is 11955.

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 55911 - 2³ = 55903 is a prime.

It is a D-number.

It is a Duffinian number.

55911 is a lucky number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 55911.

It is not an unprimeable number, because it can be changed into a prime (55901) 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, 9316 + ... + 9321.

It is an arithmetic number, because the mean of its divisors is an integer number (18638).

2⁵⁵⁹¹¹ is an apocalyptic number.

55911 is a deficient number, since it is larger than the sum of its proper divisors (18641).

55911 is a wasteful number, since it uses less digits than its factorization.

55911 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18640.

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

The square root of 55911 is about 236.4550697278. The cubic root of 55911 is about 38.2383449474.

Subtracting from 55911 its reverse (11955), we obtain a triangular number (43956 = T₂₉₆).

It can be divided in two parts, 55 and 911, that multiplied together give a palindrome (50105).

The spelling of 55911 in words is "fifty-five thousand, nine hundred eleven".