13221660 has 24 divisors (see below), whose sum is σ = 37020816. Its totient is φ = 3525760.

The previous prime is 13221647. The next prime is 13221667. The reversal of 13221660 is 6612231.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13221667) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 110121 + ... + 110240.

It is an arithmetic number, because the mean of its divisors is an integer number (1542534).

Almost surely, 2^13221660 is an apocalyptic number.

13221660 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

13221660 is an abundant number, since it is smaller than the sum of its proper divisors (23799156).

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

13221660 is a wasteful number, since it uses less digits than its factorization.

13221660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220373 (or 220371 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 13221660 is about 3636.1600624835. The cubic root of 13221660 is about 236.4623465242.

Adding to 13221660 its reverse (6612231), we get a palindrome (19833891).

The spelling of 13221660 in words is "thirteen million, two hundred twenty-one thousand, six hundred sixty".