12638440 has 16 divisors (see below), whose sum is σ = 28436580. Its totient is φ = 5055360.

The previous prime is 12638419. The next prime is 12638453. The reversal of 12638440 is 4483621.

It can be written as a sum of positive squares in 2 ways, for example, as 11035684 + 1602756 = 3322^2 + 1266^2 .

It is a junction number, because it is equal to n+sod(n) for n = 12638399 and 12638408.

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, 157941 + ... + 158020.

Almost surely, 2^12638440 is an apocalyptic number.

12638440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

12638440 is an abundant number, since it is smaller than the sum of its proper divisors (15798140).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

12638440 is a wasteful number, since it uses less digits than its factorization.

12638440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 315972 (or 315968 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 28.

The square root of 12638440 is about 3555.0583680159. The cubic root of 12638440 is about 232.9330734241.

The spelling of 12638440 in words is "twelve million, six hundred thirty-eight thousand, four hundred forty".