221217055 has 4 divisors (see below), whose sum is σ = 265460472. Its totient is φ = 176973640.

The previous prime is 221217053. The next prime is 221217067. The reversal of 221217055 is 550712122.

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

It is not a de Polignac number, because 221217055 - 2¹ = 221217053 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221217053) 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, 22121701 + ... + 22121710.

It is an arithmetic number, because the mean of its divisors is an integer number (66365118).

Almost surely, 2^221217055 is an apocalyptic number.

221217055 is a deficient number, since it is larger than the sum of its proper divisors (44243417).

221217055 is an equidigital number, since it uses as much as digits as its factorization.

221217055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44243416.

The product of its (nonzero) digits is 1400, while the sum is 25.

The square root of 221217055 is about 14873.3673053549. The cubic root of 221217055 is about 604.7922288163.

Adding to 221217055 its reverse (550712122), we get a palindrome (771929177).

The spelling of 221217055 in words is "two hundred twenty-one million, two hundred seventeen thousand, fifty-five".