12520405 has 4 divisors (see below), whose sum is σ = 15024492. Its totient is φ = 10016320.

The previous prime is 12520399. The next prime is 12520421. The reversal of 12520405 is 50402521.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3651921 + 8868484 = 1911^2 + 2978^2 .

It is not a de Polignac number, because 12520405 - 2⁹ = 12519893 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1252036 + ... + 1252045.

It is an arithmetic number, because the mean of its divisors is an integer number (3756123).

Almost surely, 2^12520405 is an apocalyptic number.

It is an amenable number.

12520405 is a deficient number, since it is larger than the sum of its proper divisors (2504087).

12520405 is an equidigital number, since it uses as much as digits as its factorization.

12520405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2504086.

The product of its (nonzero) digits is 400, while the sum is 19.

The square root of 12520405 is about 3538.4184320117. The cubic root of 12520405 is about 232.2056551888.

Adding to 12520405 its reverse (50402521), we get a palindrome (62922926).

The spelling of 12520405 in words is "twelve million, five hundred twenty thousand, four hundred five".