55811 has 12 divisors (see below), whose sum is σ = 69768. Its totient is φ = 44352.

The previous prime is 55807. The next prime is 55813. The reversal of 55811 is 11855.

It is not a de Polignac number, because 55811 - 2² = 55807 is a prime.

It is a super-2 number, since 2×55811² = 6229735442, which contains 22 as substring.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 55811.

It is not an unprimeable number, because it can be changed into a prime (55813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 800 + ... + 866.

It is an arithmetic number, because the mean of its divisors is an integer number (5814).

2⁵⁵⁸¹¹ is an apocalyptic number.

55811 is a deficient number, since it is larger than the sum of its proper divisors (13957).

55811 is a wasteful number, since it uses less digits than its factorization.

55811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98 (or 91 counting only the distinct ones).

The product of its digits is 200, while the sum is 20.

The square root of 55811 is about 236.2435184296. The cubic root of 55811 is about 38.2155341918.

Subtracting from 55811 its product of digits (200), we obtain a triangular number (55611 = T₃₃₃).

Subtracting from 55811 its reverse (11855), we obtain a triangular number (43956 = T₂₉₆).

The spelling of 55811 in words is "fifty-five thousand, eight hundred eleven".