28281730 has 8 divisors (see below), whose sum is σ = 50907132. Its totient is φ = 11312688.

The previous prime is 28281691. The next prime is 28281731. The reversal of 28281730 is 3718282.

It can be written as a sum of positive squares in 2 ways, for example, as 27279729 + 1002001 = 5223^2 + 1001^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 28281692 and 28281701.

It is not an unprimeable number, because it can be changed into a prime (28281731) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 1414077 + ... + 1414096.

Almost surely, 2^28281730 is an apocalyptic number.

28281730 is a deficient number, since it is larger than the sum of its proper divisors (22625402).

28281730 is a wasteful number, since it uses less digits than its factorization.

28281730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2828180.

The product of its (nonzero) digits is 5376, while the sum is 31.

The square root of 28281730 is about 5318.0569760017. The cubic root of 28281730 is about 304.6739505962.

The spelling of 28281730 in words is "twenty-eight million, two hundred eighty-one thousand, seven hundred thirty".