12638220381 has 24 divisors (see below), whose sum is σ = 18374723640. Its totient is φ = 8370395136.

The previous prime is 12638220373. The next prime is 12638220403. The reversal of 12638220381 is 18302283621.

12638220381 is a `hidden beast` number, since 1 + 26 + 38 + 220 + 381 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 4524714756 + 8113505625 = 67266^2 + 90075^2 .

It is not a de Polignac number, because 12638220381 - 2³ = 12638220373 is a prime.

It is a super-2 number, since 2×12638220381² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12638220341) 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 23 ways as a sum of consecutive naturals, for example, 2939025 + ... + 2943321.

It is an arithmetic number, because the mean of its divisors is an integer number (765613485).

Almost surely, 2^12638220381 is an apocalyptic number.

It is an amenable number.

12638220381 is a deficient number, since it is larger than the sum of its proper divisors (5736503259).

12638220381 is a wasteful number, since it uses less digits than its factorization.

12638220381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6365 (or 6362 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The spelling of 12638220381 in words is "twelve billion, six hundred thirty-eight million, two hundred twenty thousand, three hundred eighty-one".