221660 has 12 divisors (see below), whose sum is σ = 465528. Its totient is φ = 88656.

The previous prime is 221659. The next prime is 221671. The reversal of 221660 is 66122.

221660 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a plaindrome in base 14.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 221660.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5522 + ... + 5561.

It is an arithmetic number, because the mean of its divisors is an integer number (38794).

2²²¹⁶⁶⁰ is an apocalyptic number.

221660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221660 is an abundant number, since it is smaller than the sum of its proper divisors (243868).

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

221660 is a wasteful number, since it uses less digits than its factorization.

221660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11092 (or 11090 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 221660 is about 470.8078164177. The cubic root of 221660 is about 60.5195620097.

Adding to 221660 its reverse (66122), we get a palindrome (287782).

The spelling of 221660 in words is "two hundred twenty-one thousand, six hundred sixty".