12221660 has 48 divisors (see below), whose sum is σ = 28419552. Its totient is φ = 4377600.

The previous prime is 12221611. The next prime is 12221669. The reversal of 12221660 is 6612221.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12221669) 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, 15680 + ... + 16440.

It is an arithmetic number, because the mean of its divisors is an integer number (592074).

Almost surely, 2^12221660 is an apocalyptic number.

12221660 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 12221660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14209776).

12221660 is an abundant number, since it is smaller than the sum of its proper divisors (16197892).

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

12221660 is a wasteful number, since it uses less digits than its factorization.

12221660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 854 (or 852 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 12221660 is about 3495.9490842974. The cubic root of 12221660 is about 230.3439089521.

Adding to 12221660 its reverse (6612221), we get a palindrome (18833881).

It can be divided in two parts, 1222 and 1660, that added together give a palindrome (2882).

The spelling of 12221660 in words is "twelve million, two hundred twenty-one thousand, six hundred sixty".