12689581 has 2 divisors, whose sum is σ = 12689582. Its totient is φ = 12689580.

The previous prime is 12689507. The next prime is 12689597. The reversal of 12689581 is 18598621.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8649481 + 4040100 = 2941^2 + 2010^2 .

It is an emirp because it is prime and its reverse (18598621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12689581 - 2⁹ = 12689069 is a prime.

It is a super-2 number, since 2×12689581² = 322050931911122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12689081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6344790 + 6344791.

It is an arithmetic number, because the mean of its divisors is an integer number (6344791).

Almost surely, 2^12689581 is an apocalyptic number.

It is an amenable number.

12689581 is a deficient number, since it is larger than the sum of its proper divisors (1).

12689581 is an equidigital number, since it uses as much as digits as its factorization.

12689581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34560, while the sum is 40.

The square root of 12689581 is about 3562.2438153501. The cubic root of 12689581 is about 233.2468357394.

The spelling of 12689581 in words is "twelve million, six hundred eighty-nine thousand, five hundred eighty-one".