28720011 has 8 divisors (see below), whose sum is σ = 39016080. Its totient is φ = 18785312.

The previous prime is 28719989. The next prime is 28720037. The reversal of 28720011 is 11002782.

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

It is a cyclic number.

It is not a de Polignac number, because 28720011 - 2⁵ = 28719979 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28720011.

It is not an unprimeable number, because it can be changed into a prime (28720091) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 90156 + ... + 90473.

It is an arithmetic number, because the mean of its divisors is an integer number (4877010).

Almost surely, 2^28720011 is an apocalyptic number.

28720011 is a deficient number, since it is larger than the sum of its proper divisors (10296069).

28720011 is a wasteful number, since it uses less digits than its factorization.

28720011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180685.

The product of its (nonzero) digits is 224, while the sum is 21.

The square root of 28720011 is about 5359.1054290805. The cubic root of 28720011 is about 306.2397305455.

Adding to 28720011 its reverse (11002782), we get a palindrome (39722793).

The spelling of 28720011 in words is "twenty-eight million, seven hundred twenty thousand, eleven".