13221566 has 4 divisors (see below), whose sum is σ = 19832352. Its totient is φ = 6610782.

The previous prime is 13221553. The next prime is 13221577. The reversal of 13221566 is 66512231.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3305390 + ... + 3305393.

It is an arithmetic number, because the mean of its divisors is an integer number (4958088).

Almost surely, 2^13221566 is an apocalyptic number.

13221566 is a deficient number, since it is larger than the sum of its proper divisors (6610786).

13221566 is an equidigital number, since it uses as much as digits as its factorization.

13221566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6610785.

The product of its digits is 2160, while the sum is 26.

The square root of 13221566 is about 3636.1471367369. The cubic root of 13221566 is about 236.4617861429.

Adding to 13221566 its reverse (66512231), we get a palindrome (79733797).

The spelling of 13221566 in words is "thirteen million, two hundred twenty-one thousand, five hundred sixty-six".