12917421 has 64 divisors (see below), whose sum is σ = 22855680. Its totient is φ = 7128000.

The previous prime is 12917389. The next prime is 12917431. The reversal of 12917421 is 12471921.

12917421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 12917421 - 2⁵ = 12917389 is a prime.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12917431) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 211731 + ... + 211791.

It is an arithmetic number, because the mean of its divisors is an integer number (357120).

Almost surely, 2^12917421 is an apocalyptic number.

12917421 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12917421 is a deficient number, since it is larger than the sum of its proper divisors (9938259).

12917421 is a wasteful number, since it uses less digits than its factorization.

12917421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135 (or 129 counting only the distinct ones).

The product of its digits is 1008, while the sum is 27.

The square root of 12917421 is about 3594.0813847213. The cubic root of 12917421 is about 234.6345368140.

The spelling of 12917421 in words is "twelve million, nine hundred seventeen thousand, four hundred twenty-one".