13978728 has 24 divisors (see below), whose sum is σ = 37859250. Its totient is φ = 4659552.

The previous prime is 13978721. The next prime is 13978729. The reversal of 13978728 is 82787931.

It can be written as a sum of positive squares in only one way, i.e., 13972644 + 6084 = 3738^2 + 78^2 .

It is a tau number, because it is divible by the number of its divisors (24).

It is not an unprimeable number, because it can be changed into a prime (13978721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 97003 + ... + 97146.

Almost surely, 2^13978728 is an apocalyptic number.

13978728 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

13978728 is an abundant number, since it is smaller than the sum of its proper divisors (23880522).

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

13978728 is a wasteful number, since it uses less digits than its factorization.

13978728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 194161 (or 194154 counting only the distinct ones).

The product of its digits is 169344, while the sum is 45.

The square root of 13978728 is about 3738.8137156055. The cubic root of 13978728 is about 240.8920965735.

It can be divided in two parts, 13978 and 728, that added together give a triangular number (14706 = T₁₇₁).

The spelling of 13978728 in words is "thirteen million, nine hundred seventy-eight thousand, seven hundred twenty-eight".