28931808 has 48 divisors (see below), whose sum is σ = 76882176. Its totient is φ = 9525120.

The previous prime is 28931801. The next prime is 28931827. The reversal of 28931808 is 80813982.

It is a tau number, because it is divible by the number of its divisors (48).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28931801) 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, 6153 + ... + 9783.

It is an arithmetic number, because the mean of its divisors is an integer number (1601712).

Almost surely, 2^28931808 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28931808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38441088).

28931808 is an abundant number, since it is smaller than the sum of its proper divisors (47950368).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28931808 is a wasteful number, since it uses less digits than its factorization.

28931808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3727 (or 3719 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 39.

The square root of 28931808 is about 5378.8296124715. The cubic root of 28931808 is about 306.9906804317.

The spelling of 28931808 in words is "twenty-eight million, nine hundred thirty-one thousand, eight hundred eight".