12816221 has 16 divisors (see below), whose sum is σ = 14722560. Its totient is φ = 11043120.

The previous prime is 12816211. The next prime is 12816247. The reversal of 12816221 is 12261821.

12816221 is nontrivially palindromic in base 13.

12816221 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 12816221 - 2¹⁴ = 12799837 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12816211) 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, 45146 + ... + 45428.

It is an arithmetic number, because the mean of its divisors is an integer number (920160).

Almost surely, 2^12816221 is an apocalyptic number.

12816221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12816221 is a deficient number, since it is larger than the sum of its proper divisors (1906339).

12816221 is a wasteful number, since it uses less digits than its factorization.

12816221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 496.

The product of its digits is 384, while the sum is 23.

The square root of 12816221 is about 3579.9749999127. The cubic root of 12816221 is about 234.0201908698.

The spelling of 12816221 in words is "twelve million, eight hundred sixteen thousand, two hundred twenty-one".