28819780 has 36 divisors (see below), whose sum is σ = 66529260. Its totient is φ = 10479040.

The previous prime is 28819741. The next prime is 28819783. The reversal of 28819780 is 8791882.

It can be written as a sum of positive squares in 2 ways, for example, as 10036224 + 18783556 = 3168^2 + 4334^2 .

It is not an unprimeable number, because it can be changed into a prime (28819783) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3535 + ... + 8374.

It is an arithmetic number, because the mean of its divisors is an integer number (1848035).

Almost surely, 2^28819780 is an apocalyptic number.

28819780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28819780 is an abundant number, since it is smaller than the sum of its proper divisors (37709480).

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

28819780 is a wasteful number, since it uses less digits than its factorization.

28819780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11940 (or 11927 counting only the distinct ones).

The product of its (nonzero) digits is 64512, while the sum is 43.

The square root of 28819780 is about 5368.4057223723. The cubic root of 28819780 is about 306.5939309750.

The spelling of 28819780 in words is "twenty-eight million, eight hundred nineteen thousand, seven hundred eighty".