221336660 has 12 divisors (see below), whose sum is σ = 464807028. Its totient is φ = 88534656.

The previous prime is 221336653. The next prime is 221336663. The reversal of 221336660 is 66633122.

It can be written as a sum of positive squares in 2 ways, for example, as 118679236 + 102657424 = 10894^2 + 10132^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221336663) 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, 5533397 + ... + 5533436.

It is an arithmetic number, because the mean of its divisors is an integer number (38733919).

Almost surely, 2^221336660 is an apocalyptic number.

221336660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221336660 is an abundant number, since it is smaller than the sum of its proper divisors (243470368).

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

221336660 is a wasteful number, since it uses less digits than its factorization.

221336660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11066842 (or 11066840 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 29.

The square root of 221336660 is about 14877.3875394842. The cubic root of 221336660 is about 604.9012064625.

Adding to 221336660 its reverse (66633122), we get a palindrome (287969782).

The spelling of 221336660 in words is "two hundred twenty-one million, three hundred thirty-six thousand, six hundred sixty".