12817421 has 2 divisors, whose sum is σ = 12817422. Its totient is φ = 12817420.

The previous prime is 12817373. The next prime is 12817459. The reversal of 12817421 is 12471821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12348196 + 469225 = 3514^2 + 685^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12817421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12817471) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6408710 + 6408711.

It is an arithmetic number, because the mean of its divisors is an integer number (6408711).

Almost surely, 2^12817421 is an apocalyptic number.

It is an amenable number.

12817421 is a deficient number, since it is larger than the sum of its proper divisors (1).

12817421 is an equidigital number, since it uses as much as digits as its factorization.

12817421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 896, while the sum is 26.

The square root of 12817421 is about 3580.1425949255. The cubic root of 12817421 is about 234.0274945169.

The spelling of 12817421 in words is "twelve million, eight hundred seventeen thousand, four hundred twenty-one".