13001221 has 4 divisors (see below), whose sum is σ = 13019692. Its totient is φ = 12982752.

The previous prime is 13001213. The next prime is 13001237. The reversal of 13001221 is 12210031.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12210031 = 499 ⋅24469.

It can be written as a sum of positive squares in 2 ways, for example, as 12173121 + 828100 = 3489^2 + 910^2 .

It is a cyclic number.

It is not a de Polignac number, because 13001221 - 2³ = 13001213 is a prime.

It is a Duffinian number.

13001221 is a modest number, since divided by 1221 gives 13 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 13001198 and 13001207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13001291) 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, 8136 + ... + 9601.

It is an arithmetic number, because the mean of its divisors is an integer number (3254923).

Almost surely, 2^13001221 is an apocalyptic number.

It is an amenable number.

13001221 is a deficient number, since it is larger than the sum of its proper divisors (18471).

13001221 is an equidigital number, since it uses as much as digits as its factorization.

13001221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18470.

The product of its (nonzero) digits is 12, while the sum is 10.

The square root of 13001221 is about 3605.7205937233. The cubic root of 13001221 is about 235.1408300279.

Adding to 13001221 its reverse (12210031), we get a palindrome (25211252).

The spelling of 13001221 in words is "thirteen million, one thousand, two hundred twenty-one".