28705911 has 32 divisors (see below), whose sum is σ = 45178560. Its totient is φ = 16041984.

The previous prime is 28705891. The next prime is 28705921. The reversal of 28705911 is 11950782.

It is not a de Polignac number, because 28705911 - 2⁶ = 28705847 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28705921) 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 31 ways as a sum of consecutive naturals, for example, 18481 + ... + 19973.

It is an arithmetic number, because the mean of its divisors is an integer number (1411830).

Almost surely, 2^28705911 is an apocalyptic number.

28705911 is a deficient number, since it is larger than the sum of its proper divisors (16472649).

28705911 is a wasteful number, since it uses less digits than its factorization.

28705911 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1555.

The product of its (nonzero) digits is 5040, while the sum is 33.

The square root of 28705911 is about 5357.7897495143. The cubic root of 28705911 is about 306.1896065278.

The spelling of 28705911 in words is "twenty-eight million, seven hundred five thousand, nine hundred eleven".