55218559 has 4 divisors (see below), whose sum is σ = 60238440. Its totient is φ = 50198680.

The previous prime is 55218529. The next prime is 55218563. The reversal of 55218559 is 95581255.

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

It is a cyclic number.

It is not a de Polignac number, because 55218559 - 2¹⁹ = 54694271 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55218529) 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, 2509924 + ... + 2509945.

It is an arithmetic number, because the mean of its divisors is an integer number (15059610).

Almost surely, 2^55218559 is an apocalyptic number.

55218559 is a deficient number, since it is larger than the sum of its proper divisors (5019881).

55218559 is a wasteful number, since it uses less digits than its factorization.

55218559 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5019880.

The product of its digits is 90000, while the sum is 40.

The square root of 55218559 is about 7430.9191221544. The cubic root of 55218559 is about 380.7983193755.

The spelling of 55218559 in words is "fifty-five million, two hundred eighteen thousand, five hundred fifty-nine".