221306656 has 24 divisors (see below), whose sum is σ = 450723420. Its totient is φ = 106837248.

The previous prime is 221306651. The next prime is 221306669. The reversal of 221306656 is 656603122.

It can be written as a sum of positive squares in 2 ways, for example, as 216090000 + 5216656 = 14700^2 + 2284^2 .

It is not an unprimeable number, because it can be changed into a prime (221306651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 118311 + ... + 120166.

Almost surely, 2^221306656 is an apocalyptic number.

It is an amenable number.

221306656 is an abundant number, since it is smaller than the sum of its proper divisors (229416764).

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

221306656 is a wasteful number, since it uses less digits than its factorization.

221306656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 238516 (or 238508 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 31.

The square root of 221306656 is about 14876.3791293446. The cubic root of 221306656 is about 604.8738721203.

Adding to 221306656 its reverse (656603122), we get a palindrome (877909778).

It can be divided in two parts, 2213066 and 56, that added together give a palindrome (2213122).

The spelling of 221306656 in words is "two hundred twenty-one million, three hundred six thousand, six hundred fifty-six".