13681728 has 42 divisors (see below), whose sum is σ = 39217854. Its totient is φ = 4560384.

The previous prime is 13681727. The next prime is 13681739. The reversal of 13681728 is 82718631.

It can be written as a sum of positive squares in only one way, i.e., 12616704 + 1065024 = 3552^2 + 1032^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 13681692 and 13681701.

It is not an unprimeable number, because it can be changed into a prime (13681721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 11301 + ... + 12452.

Almost surely, 2^13681728 is an apocalyptic number.

13681728 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

13681728 is an abundant number, since it is smaller than the sum of its proper divisors (25536126).

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

13681728 is a wasteful number, since it uses less digits than its factorization.

13681728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23771 (or 23758 counting only the distinct ones).

The product of its digits is 16128, while the sum is 36.

The square root of 13681728 is about 3698.8819932515. The cubic root of 13681728 is about 239.1738259150.

The spelling of 13681728 in words is "thirteen million, six hundred eighty-one thousand, seven hundred twenty-eight".