13221021 has 16 divisors (see below), whose sum is σ = 20067840. Its totient is φ = 7663920.

The previous prime is 13221011. The next prime is 13221029. The reversal of 13221021 is 12012231.

It is not a de Polignac number, because 13221021 - 2⁵ = 13220989 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 13220988 and 13221006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13221029) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7951 + ... + 9468.

It is an arithmetic number, because the mean of its divisors is an integer number (1254240).

Almost surely, 2^13221021 is an apocalyptic number.

13221021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

13221021 is a deficient number, since it is larger than the sum of its proper divisors (6846819).

13221021 is a wasteful number, since it uses less digits than its factorization.

13221021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17456.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 13221021 is about 3636.0721940028. The cubic root of 13221021 is about 236.4585370713.

Adding to 13221021 its reverse (12012231), we get a palindrome (25233252).

It can be divided in two parts, 132210 and 21, that added together give a palindrome (132231).

The spelling of 13221021 in words is "thirteen million, two hundred twenty-one thousand, twenty-one".