28781886 has 32 divisors (see below), whose sum is σ = 66401280. Its totient is φ = 8146656.

The previous prime is 28781881. The next prime is 28781917. The reversal of 28781886 is 68818782.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28781881) 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, 1435 + ... + 7721.

It is an arithmetic number, because the mean of its divisors is an integer number (2075040).

Almost surely, 2^28781886 is an apocalyptic number.

28781886 is an abundant number, since it is smaller than the sum of its proper divisors (37619394).

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

28781886 is a wasteful number, since it uses less digits than its factorization.

28781886 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6408.

The product of its digits is 344064, while the sum is 48.

The square root of 28781886 is about 5364.8752082411. The cubic root of 28781886 is about 306.4594959192.

The spelling of 28781886 in words is "twenty-eight million, seven hundred eighty-one thousand, eight hundred eighty-six".