55243221 has 16 divisors (see below), whose sum is σ = 80569920. Its totient is φ = 33390720.

The previous prime is 55243213. The next prime is 55243229. The reversal of 55243221 is 12234255.

It is an interprime number because it is at equal distance from previous prime (55243213) and next prime (55243229).

It is not a de Polignac number, because 55243221 - 2³ = 55243213 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 55243191 and 55243200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55243229) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11451 + ... + 15543.

It is an arithmetic number, because the mean of its divisors is an integer number (5035620).

Almost surely, 2^55243221 is an apocalyptic number.

It is an amenable number.

55243221 is a deficient number, since it is larger than the sum of its proper divisors (25326699).

55243221 is a wasteful number, since it uses less digits than its factorization.

55243221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4516.

The product of its digits is 2400, while the sum is 24.

The square root of 55243221 is about 7432.5783547838. The cubic root of 55243221 is about 380.8550023129.

Adding to 55243221 its reverse (12234255), we get a palindrome (67477476).

The spelling of 55243221 in words is "fifty-five million, two hundred forty-three thousand, two hundred twenty-one".