12999221 has 4 divisors (see below), whose sum is σ = 13447500. Its totient is φ = 12550944.

The previous prime is 12999193. The next prime is 12999223. The reversal of 12999221 is 12299921.

12999221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12299921 = 1787 ⋅6883.

It can be written as a sum of positive squares in 2 ways, for example, as 10562500 + 2436721 = 3250^2 + 1561^2 .

It is a cyclic number.

It is not a de Polignac number, because 12999221 - 2⁶ = 12999157 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 (12999223) 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, 224096 + ... + 224153.

It is an arithmetic number, because the mean of its divisors is an integer number (3361875).

Almost surely, 2^12999221 is an apocalyptic number.

It is an amenable number.

12999221 is a deficient number, since it is larger than the sum of its proper divisors (448279).

12999221 is an equidigital number, since it uses as much as digits as its factorization.

12999221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 448278.

The product of its digits is 5832, while the sum is 35.

The square root of 12999221 is about 3605.4432459824. The cubic root of 12999221 is about 235.1287720379.

The spelling of 12999221 in words is "twelve million, nine hundred ninety-nine thousand, two hundred twenty-one".