28380728 has 8 divisors (see below), whose sum is σ = 53213880. Its totient is φ = 14190360.

The previous prime is 28380727. The next prime is 28380743. The reversal of 28380728 is 82708382.

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 28380691 and 28380700.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28380727) 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 as a sum of consecutive naturals, namely, 1773788 + ... + 1773803.

It is an arithmetic number, because the mean of its divisors is an integer number (6651735).

Almost surely, 2^28380728 is an apocalyptic number.

It is an amenable number.

28380728 is a deficient number, since it is larger than the sum of its proper divisors (24833152).

28380728 is a wasteful number, since it uses less digits than its factorization.

28380728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3547597 (or 3547593 counting only the distinct ones).

The product of its (nonzero) digits is 43008, while the sum is 38.

The square root of 28380728 is about 5327.3565677548. The cubic root of 28380728 is about 305.0290324420.

The spelling of 28380728 in words is "twenty-eight million, three hundred eighty thousand, seven hundred twenty-eight".