12722221 has 8 divisors (see below), whose sum is σ = 13112504. Its totient is φ = 12337920.

The previous prime is 12722219. The next prime is 12722233. The reversal of 12722221 is 12222721.

It can be written as a sum of positive squares in 4 ways, for example, as 570025 + 12152196 = 755^2 + 3486^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 12722221 - 2¹ = 12722219 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 (12722261) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3025 + ... + 5881.

It is an arithmetic number, because the mean of its divisors is an integer number (1639063).

Almost surely, 2^12722221 is an apocalyptic number.

It is an amenable number.

12722221 is a deficient number, since it is larger than the sum of its proper divisors (390283).

12722221 is an equidigital number, since it uses as much as digits as its factorization.

12722221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2991.

The product of its digits is 224, while the sum is 19.

The square root of 12722221 is about 3566.8222551734. The cubic root of 12722221 is about 233.4466494953.

Adding to 12722221 its reverse (12222721), we get a palindrome (24944942).

Subtracting from 12722221 its reverse (12222721), we obtain a triangular number (499500 = T₉₉₉).

The spelling of 12722221 in words is "twelve million, seven hundred twenty-two thousand, two hundred twenty-one".