12400639 has 4 divisors (see below), whose sum is σ = 12443256. Its totient is φ = 12358024.

The previous prime is 12400627. The next prime is 12400643. The reversal of 12400639 is 93600421.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93600421 = 353 ⋅265157.

It is a cyclic number.

It is not a de Polignac number, because 12400639 - 2⁷ = 12400511 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12400669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20869 + ... + 21454.

It is an arithmetic number, because the mean of its divisors is an integer number (3110814).

Almost surely, 2^12400639 is an apocalyptic number.

12400639 is a deficient number, since it is larger than the sum of its proper divisors (42617).

12400639 is an equidigital number, since it uses as much as digits as its factorization.

12400639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42616.

The product of its (nonzero) digits is 1296, while the sum is 25.

The square root of 12400639 is about 3521.4541030659. The cubic root of 12400639 is about 231.4628812510.

The spelling of 12400639 in words is "twelve million, four hundred thousand, six hundred thirty-nine".