13220621 has 4 divisors (see below), whose sum is σ = 13309500. Its totient is φ = 13131744.

The previous prime is 13220609. The next prime is 13220629. The reversal of 13220621 is 12602231.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1755625 + 11464996 = 1325^2 + 3386^2 .

It is a cyclic number.

It is not a de Polignac number, because 13220621 - 2¹⁴ = 13204237 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 13220621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13220629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44216 + ... + 44513.

It is an arithmetic number, because the mean of its divisors is an integer number (3327375).

Almost surely, 2^13220621 is an apocalyptic number.

It is an amenable number.

13220621 is a deficient number, since it is larger than the sum of its proper divisors (88879).

13220621 is an equidigital number, since it uses as much as digits as its factorization.

13220621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88878.

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

The square root of 13220621 is about 3636.0171891783. The cubic root of 13220621 is about 236.4561523748.

Adding to 13220621 its reverse (12602231), we get a palindrome (25822852).

The spelling of 13220621 in words is "thirteen million, two hundred twenty thousand, six hundred twenty-one".