12509865 has 24 divisors (see below), whose sum is σ = 21902400. Its totient is φ = 6604704.

The previous prime is 12509857. The next prime is 12509869. The reversal of 12509865 is 56890521.

It is a happy number.

It is not a de Polignac number, because 12509865 - 2³ = 12509857 is a prime.

It is not an unprimeable number, because it can be changed into a prime (12509869) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3286 + ... + 5984.

It is an arithmetic number, because the mean of its divisors is an integer number (912600).

Almost surely, 2^12509865 is an apocalyptic number.

12509865 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

12509865 is a deficient number, since it is larger than the sum of its proper divisors (9392535).

12509865 is a wasteful number, since it uses less digits than its factorization.

12509865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2813 (or 2810 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 36.

The square root of 12509865 is about 3536.9287524631. The cubic root of 12509865 is about 232.1404779920.

The spelling of 12509865 in words is "twelve million, five hundred nine thousand, eight hundred sixty-five".