12638581 has 2 divisors, whose sum is σ = 12638582. Its totient is φ = 12638580.

The previous prime is 12638551. The next prime is 12638621. The reversal of 12638581 is 18583621.

12638581 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10297681 + 2340900 = 3209^2 + 1530^2 .

It is a cyclic number.

It is not a de Polignac number, because 12638581 - 2⁷ = 12638453 is a prime.

It is a super-4 number, since 4×12638581⁴ (a number of 30 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12638501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6319290 + 6319291.

It is an arithmetic number, because the mean of its divisors is an integer number (6319291).

Almost surely, 2^12638581 is an apocalyptic number.

It is an amenable number.

12638581 is a deficient number, since it is larger than the sum of its proper divisors (1).

12638581 is an equidigital number, since it uses as much as digits as its factorization.

12638581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11520, while the sum is 34.

The square root of 12638581 is about 3555.0781988586. The cubic root of 12638581 is about 232.9339396555.

The spelling of 12638581 in words is "twelve million, six hundred thirty-eight thousand, five hundred eighty-one".