12640423 has 4 divisors (see below), whose sum is σ = 12948768. Its totient is φ = 12332080.

The previous prime is 12640399. The next prime is 12640427. The reversal of 12640423 is 32404621.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 32404621 = 2243 ⋅14447.

It is a cyclic number.

It is not a de Polignac number, because 12640423 - 2¹⁷ = 12509351 is a prime.

It is a Smith number, since the sum of its digits (22) 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 a junction number, because it is equal to n+sod(n) for n = 12640394 and 12640403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12640427) 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, 154111 + ... + 154192.

It is an arithmetic number, because the mean of its divisors is an integer number (3237192).

Almost surely, 2^12640423 is an apocalyptic number.

12640423 is a deficient number, since it is larger than the sum of its proper divisors (308345).

12640423 is an equidigital number, since it uses as much as digits as its factorization.

12640423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308344.

The product of its (nonzero) digits is 1152, while the sum is 22.

The square root of 12640423 is about 3555.3372554513. The cubic root of 12640423 is about 232.9452553634.

The spelling of 12640423 in words is "twelve million, six hundred forty thousand, four hundred twenty-three".