28785813 has 32 divisors (see below), whose sum is σ = 45696000. Its totient is φ = 15776640.

The previous prime is 28785803. The next prime is 28785821. The reversal of 28785813 is 31858782.

It is a happy number.

It is not a de Polignac number, because 28785813 - 2⁶ = 28785749 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28785803) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 57438 + ... + 57936.

It is an arithmetic number, because the mean of its divisors is an integer number (1428000).

Almost surely, 2^28785813 is an apocalyptic number.

It is an amenable number.

28785813 is a deficient number, since it is larger than the sum of its proper divisors (16910187).

28785813 is a wasteful number, since it uses less digits than its factorization.

28785813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 617.

The product of its digits is 107520, while the sum is 42.

The square root of 28785813 is about 5365.2411874957. The cubic root of 28785813 is about 306.4734330614.

The spelling of 28785813 in words is "twenty-eight million, seven hundred eighty-five thousand, eight hundred thirteen".