28721017 has 8 divisors (see below), whose sum is σ = 30973824. Its totient is φ = 26474448.

The previous prime is 28720987. The next prime is 28721029. The reversal of 28721017 is 71012782.

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

It is not a de Polignac number, because 28721017 - 2²³ = 20332409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28721317) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13338 + ... + 15340.

It is an arithmetic number, because the mean of its divisors is an integer number (3871728).

Almost surely, 2^28721017 is an apocalyptic number.

It is an amenable number.

28721017 is a deficient number, since it is larger than the sum of its proper divisors (2252807).

28721017 is a wasteful number, since it uses less digits than its factorization.

28721017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3119.

The product of its (nonzero) digits is 1568, while the sum is 28.

The square root of 28721017 is about 5359.1992872070. The cubic root of 28721017 is about 306.2433061427.

Adding to 28721017 its reverse (71012782), we get a palindrome (99733799).

The spelling of 28721017 in words is "twenty-eight million, seven hundred twenty-one thousand, seventeen".