28789920 has 72 divisors (see below), whose sum is σ = 98250516. Its totient is φ = 7676928.

The previous prime is 28789903. The next prime is 28789931. The reversal of 28789920 is 2998782.

It can be written as a sum of positive squares in 2 ways, for example, as 28772496 + 17424 = 5364^2 + 132^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8557 + ... + 11436.

Almost surely, 2^28789920 is an apocalyptic number.

28789920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28789920 is an abundant number, since it is smaller than the sum of its proper divisors (69460596).

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

28789920 is a wasteful number, since it uses less digits than its factorization.

28789920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20014 (or 20003 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The square root of 28789920 is about 5365.6239152591. The cubic root of 28789920 is about 306.4880076776.

The spelling of 28789920 in words is "twenty-eight million, seven hundred eighty-nine thousand, nine hundred twenty".