12738421 has 2 divisors, whose sum is σ = 12738422. Its totient is φ = 12738420.

The previous prime is 12738419. The next prime is 12738431. The reversal of 12738421 is 12483721.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12567025 + 171396 = 3545^2 + 414^2 .

It is a cyclic number.

It is not a de Polignac number, because 12738421 - 2¹ = 12738419 is a prime.

Together with 12738419, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 12738421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12738431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6369210 + 6369211.

It is an arithmetic number, because the mean of its divisors is an integer number (6369211).

Almost surely, 2^12738421 is an apocalyptic number.

It is an amenable number.

12738421 is a deficient number, since it is larger than the sum of its proper divisors (1).

12738421 is an equidigital number, since it uses as much as digits as its factorization.

12738421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2688, while the sum is 28.

The square root of 12738421 is about 3569.0924616771. The cubic root of 12738421 is about 233.5456948753.

The spelling of 12738421 in words is "twelve million, seven hundred thirty-eight thousand, four hundred twenty-one".