12638819 has 4 divisors (see below), whose sum is σ = 13304040. Its totient is φ = 11973600.

The previous prime is 12638807. The next prime is 12638827. The reversal of 12638819 is 91883621.

12638819 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 91883621 = 109 ⋅842969.

It is a cyclic number.

It is not a de Polignac number, because 12638819 - 2¹⁶ = 12573283 is a prime.

It is a super-2 number, since 2×12638819² = 319479491429522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12638839) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 332582 + ... + 332619.

It is an arithmetic number, because the mean of its divisors is an integer number (3326010).

Almost surely, 2^12638819 is an apocalyptic number.

12638819 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

12638819 is a deficient number, since it is larger than the sum of its proper divisors (665221).

12638819 is an equidigital number, since it uses as much as digits as its factorization.

12638819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 665220.

The product of its digits is 20736, while the sum is 38.

The square root of 12638819 is about 3555.1116719451. Note that the first 3 decimals coincide. The cubic root of 12638819 is about 232.9354017904.

The spelling of 12638819 in words is "twelve million, six hundred thirty-eight thousand, eight hundred nineteen".