12640889 has 2 divisors, whose sum is σ = 12640890. Its totient is φ = 12640888.

The previous prime is 12640879. The next prime is 12640891. The reversal of 12640889 is 98804621.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11002489 + 1638400 = 3317^2 + 1280^2 .

It is an emirp because it is prime and its reverse (98804621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12640889 - 2⁸ = 12640633 is a prime.

Together with 12640891, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (12640819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6320444 + 6320445.

It is an arithmetic number, because the mean of its divisors is an integer number (6320445).

Almost surely, 2^12640889 is an apocalyptic number.

It is an amenable number.

12640889 is a deficient number, since it is larger than the sum of its proper divisors (1).

12640889 is an equidigital number, since it uses as much as digits as its factorization.

12640889 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27648, while the sum is 38.

The square root of 12640889 is about 3555.4027901210. The cubic root of 12640889 is about 232.9481179036.

The spelling of 12640889 in words is "twelve million, six hundred forty thousand, eight hundred eighty-nine".