28779840 has 112 divisors (see below), whose sum is σ = 101559360. Its totient is φ = 7672320.

The previous prime is 28779823. The next prime is 28779847. The reversal of 28779840 is 4897782.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28779847) 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 15 ways as a sum of consecutive naturals, for example, 6975 + ... + 10305.

It is an arithmetic number, because the mean of its divisors is an integer number (906780).

Almost surely, 2^28779840 is an apocalyptic number.

28779840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28779840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (50779680).

28779840 is an abundant number, since it is smaller than the sum of its proper divisors (72779520).

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

28779840 is a wasteful number, since it uses less digits than its factorization.

28779840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3357 (or 3341 counting only the distinct ones).

The product of its (nonzero) digits is 225792, while the sum is 45.

The square root of 28779840 is about 5364.6845200813. The cubic root of 28779840 is about 306.4522340487.

The spelling of 28779840 in words is "twenty-eight million, seven hundred seventy-nine thousand, eight hundred forty".