28391011 has 8 divisors (see below), whose sum is σ = 31147200. Its totient is φ = 25664040.

The previous prime is 28390981. The next prime is 28391017. The reversal of 28391011 is 11019382.

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 28391011 - 2⁵ = 28390979 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28391017) 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 7 ways as a sum of consecutive naturals, for example, 5241 + ... + 9178.

It is an arithmetic number, because the mean of its divisors is an integer number (3893400).

Almost surely, 2^28391011 is an apocalyptic number.

28391011 is a deficient number, since it is larger than the sum of its proper divisors (2756189).

28391011 is a wasteful number, since it uses less digits than its factorization.

28391011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14609.

The product of its (nonzero) digits is 432, while the sum is 25.

The square root of 28391011 is about 5328.3215931473. The cubic root of 28391011 is about 305.0658677056.

The spelling of 28391011 in words is "twenty-eight million, three hundred ninety-one thousand, eleven".