28909780 has 24 divisors (see below), whose sum is σ = 61568640. Its totient is φ = 11400480.

The previous prime is 28909739. The next prime is 28909787. The reversal of 28909780 is 8790982.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28909787) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8760 + ... + 11599.

It is an arithmetic number, because the mean of its divisors is an integer number (2565360).

Almost surely, 2^28909780 is an apocalyptic number.

28909780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28909780 is an abundant number, since it is smaller than the sum of its proper divisors (32658860).

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

28909780 is a wasteful number, since it uses less digits than its factorization.

28909780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20439 (or 20437 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 43.

The square root of 28909780 is about 5376.7815652117. The cubic root of 28909780 is about 306.9127488154.

The spelling of 28909780 in words is "twenty-eight million, nine hundred nine thousand, seven hundred eighty".