13991328 has 144 divisors (see below), whose sum is σ = 44442216. Its totient is φ = 4147200.

The previous prime is 13991309. The next prime is 13991333. The reversal of 13991328 is 82319931.

It can be written as a sum of positive squares in 4 ways, for example, as 13927824 + 63504 = 3732^2 + 252^2 .

It is a tau number, because it is divible by the number of its divisors (144).

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

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 13991292 and 13991301.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 138478 + ... + 138578.

Almost surely, 2^13991328 is an apocalyptic number.

13991328 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 13991328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22221108).

13991328 is an abundant number, since it is smaller than the sum of its proper divisors (30450888).

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

13991328 is a wasteful number, since it uses less digits than its factorization.

13991328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167 (or 156 counting only the distinct ones).

The product of its digits is 11664, while the sum is 36.

The square root of 13991328 is about 3740.4983625180. The cubic root of 13991328 is about 240.9644524396.

The spelling of 13991328 in words is "thirteen million, nine hundred ninety-one thousand, three hundred twenty-eight".