13681638 has 24 divisors (see below), whose sum is σ = 30446208. Its totient is φ = 4437072.

The previous prime is 13681621. The next prime is 13681639. The reversal of 13681638 is 83618631.

13681638 is a `hidden beast` number, since 13 + 6 + 8 + 1 + 638 = 666.

13681638 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13681639) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9606 + ... + 10937.

It is an arithmetic number, because the mean of its divisors is an integer number (1268592).

Almost surely, 2^13681638 is an apocalyptic number.

13681638 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

13681638 is an abundant number, since it is smaller than the sum of its proper divisors (16764570).

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

13681638 is a wasteful number, since it uses less digits than its factorization.

13681638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20588 (or 20585 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 13681638 is about 3698.8698273932. The cubic root of 13681638 is about 239.1733014761.

The spelling of 13681638 in words is "thirteen million, six hundred eighty-one thousand, six hundred thirty-eight".