13221709 has 4 divisors (see below), whose sum is σ = 13677660. Its totient is φ = 12765760.

The previous prime is 13221697. The next prime is 13221737. The reversal of 13221709 is 90712231.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90712231 = 31 ⋅2926201.

It can be written as a sum of positive squares in 2 ways, for example, as 8684809 + 4536900 = 2947^2 + 2130^2 .

It is a cyclic number.

It is not a de Polignac number, because 13221709 - 2⁷ = 13221581 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13221749) 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, 227932 + ... + 227989.

It is an arithmetic number, because the mean of its divisors is an integer number (3419415).

Almost surely, 2^13221709 is an apocalyptic number.

It is an amenable number.

13221709 is a deficient number, since it is larger than the sum of its proper divisors (455951).

13221709 is an equidigital number, since it uses as much as digits as its factorization.

13221709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 455950.

The product of its (nonzero) digits is 756, while the sum is 25.

The square root of 13221709 is about 3636.1668003545. The cubic root of 13221709 is about 236.4626386368.

The spelling of 13221709 in words is "thirteen million, two hundred twenty-one thousand, seven hundred nine".