12909221 has 8 divisors (see below), whose sum is σ = 13934424. Its totient is φ = 11888640.

The previous prime is 12909217. The next prime is 12909223. The reversal of 12909221 is 12290921.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 5013121 + 7896100 = 2239^2 + 2810^2 .

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 12909221 - 2² = 12909217 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 (12909223) 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 7 ways as a sum of consecutive naturals, for example, 6641 + ... + 8361.

It is an arithmetic number, because the mean of its divisors is an integer number (1741803).

Almost surely, 2^12909221 is an apocalyptic number.

It is an amenable number.

12909221 is a deficient number, since it is larger than the sum of its proper divisors (1025203).

12909221 is a wasteful number, since it uses less digits than its factorization.

12909221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2311.

The product of its (nonzero) digits is 648, while the sum is 26.

The square root of 12909221 is about 3592.9404392503. The cubic root of 12909221 is about 234.5848775085.

The spelling of 12909221 in words is "twelve million, nine hundred nine thousand, two hundred twenty-one".