13781328 has 80 divisors (see below), whose sum is σ = 39806976. Its totient is φ = 4072320.

The previous prime is 13781321. The next prime is 13781357. The reversal of 13781328 is 82318731.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (33).

Its product of digits (8064) is a multiple of the sum of its prime factors (672).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13781321) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22401 + ... + 23007.

Almost surely, 2^13781328 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 13781328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (19903488).

13781328 is an abundant number, since it is smaller than the sum of its proper divisors (26025648).

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

13781328 is a wasteful number, since it uses less digits than its factorization.

13781328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 672 (or 666 counting only the distinct ones).

The product of its digits is 8064, while the sum is 33.

The square root of 13781328 is about 3712.3211068010. The cubic root of 13781328 is about 239.7528010291.

The spelling of 13781328 in words is "thirteen million, seven hundred eighty-one thousand, three hundred twenty-eight".