12640505 has 16 divisors (see below), whose sum is σ = 15667344. Its totient is φ = 9784320.

The previous prime is 12640499. The next prime is 12640513. The reversal of 12640505 is 50504621.

It can be written as a sum of positive squares in 8 ways, for example, as 1776889 + 10863616 = 1333^2 + 3296^2 .

It is not a de Polignac number, because 12640505 - 2⁴ = 12640489 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 in 15 ways as a sum of consecutive naturals, for example, 40229 + ... + 40541.

It is an arithmetic number, because the mean of its divisors is an integer number (979209).

Almost surely, 2^12640505 is an apocalyptic number.

It is an amenable number.

12640505 is a deficient number, since it is larger than the sum of its proper divisors (3026839).

12640505 is a wasteful number, since it uses less digits than its factorization.

12640505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 556.

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 12640505 is about 3555.3487873906. The cubic root of 12640505 is about 232.9457590773.

The spelling of 12640505 in words is "twelve million, six hundred forty thousand, five hundred five".