12947221 has 8 divisors (see below), whose sum is σ = 15099200. Its totient is φ = 11097324.

The previous prime is 12947213. The next prime is 12947237. The reversal of 12947221 is 12274921.

12947221 is digitally balanced in base 2 and base 8, because in such bases it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 12947221 - 2³ = 12947213 is a prime.

It is a Duffinian number.

12947221 is strictly pandigital in base 8.

It is a self number, because there is not a number n which added to its sum of digits gives 12947221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12947261) 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, 18531 + ... + 19216.

It is an arithmetic number, because the mean of its divisors is an integer number (1887400).

Almost surely, 2^12947221 is an apocalyptic number.

It is an amenable number.

12947221 is a deficient number, since it is larger than the sum of its proper divisors (2151979).

12947221 is an frugal number, since it uses more digits than its factorization.

12947221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37768 (or 37754 counting only the distinct ones).

The product of its digits is 2016, while the sum is 28.

The square root of 12947221 is about 3598.2247011547. The cubic root of 12947221 is about 234.8148292329.

It can be divided in two parts, 1294 and 7221, that added together give a triangular number (8515 = T₁₃₀).

The spelling of 12947221 in words is "twelve million, nine hundred forty-seven thousand, two hundred twenty-one".