12900865 has 4 divisors (see below), whose sum is σ = 15481044. Its totient is φ = 10320688.

The previous prime is 12900863. The next prime is 12900869. The reversal of 12900865 is 56800921.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56800921 = 79 ⋅718999.

It can be written as a sum of positive squares in 2 ways, for example, as 9199089 + 3701776 = 3033^2 + 1924^2 .

It is a cyclic number.

It is not a de Polignac number, because 12900865 - 2¹ = 12900863 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12900863) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1290082 + ... + 1290091.

It is an arithmetic number, because the mean of its divisors is an integer number (3870261).

Almost surely, 2^12900865 is an apocalyptic number.

It is an amenable number.

12900865 is a deficient number, since it is larger than the sum of its proper divisors (2580179).

12900865 is an equidigital number, since it uses as much as digits as its factorization.

12900865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2580178.

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 12900865 is about 3591.7774151526. Note that the first 3 decimals coincide. The cubic root of 12900865 is about 234.5342518272.

The spelling of 12900865 in words is "twelve million, nine hundred thousand, eight hundred sixty-five".