28921685 has 16 divisors (see below), whose sum is σ = 38174976. Its totient is φ = 20900928.

The previous prime is 28921681. The next prime is 28921693. The reversal of 28921685 is 58612982.

It is a cyclic number.

It is not a de Polignac number, because 28921685 - 2² = 28921681 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28921681) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1679 + ... + 7788.

It is an arithmetic number, because the mean of its divisors is an integer number (2385936).

Almost surely, 2^28921685 is an apocalyptic number.

It is an amenable number.

28921685 is a deficient number, since it is larger than the sum of its proper divisors (9253291).

28921685 is a wasteful number, since it uses less digits than its factorization.

28921685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9532.

The product of its digits is 69120, while the sum is 41.

The square root of 28921685 is about 5377.8885261783. Note that the first 3 decimals coincide. The cubic root of 28921685 is about 306.9548717561.

The spelling of 28921685 in words is "twenty-eight million, nine hundred twenty-one thousand, six hundred eighty-five".