55216 has 40 divisors (see below), whose sum is σ = 133920. Its totient is φ = 21504.

The previous prime is 55213. The next prime is 55217. The reversal of 55216 is 61255.

55216 = 25² + 26² + ... + 56².

It is a happy number.

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 55193 and 55202.

It is not an unprimeable number, because it can be changed into a prime (55213) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1890 + ... + 1918.

It is an arithmetic number, because the mean of its divisors is an integer number (3348).

2⁵⁵²¹⁶ is an apocalyptic number.

55216 is a gapful number since it is divisible by the number (56) formed by its first and last digit.

55216 is the 136-th octagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 55216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (66960).

55216 is an abundant number, since it is smaller than the sum of its proper divisors (78704).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

55216 is a wasteful number, since it uses less digits than its factorization.

55216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61 (or 55 counting only the distinct ones).

The product of its digits is 300, while the sum is 19.

The square root of 55216 is about 234.9808502836. The cubic root of 55216 is about 38.0792436825.

The spelling of 55216 in words is "fifty-five thousand, two hundred sixteen".