28777680 has 100 divisors (see below), whose sum is σ = 99971652. Its totient is φ = 7672320.

The previous prime is 28777667. The next prime is 28777691. The reversal of 28777680 is 8677782.

It can be written as a sum of positive squares in 2 ways, for example, as 10732176 + 18045504 = 3276^2 + 4248^2 .

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 4260 + ... + 8700.

Almost surely, 2^28777680 is an apocalyptic number.

28777680 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 28777680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (49985826).

28777680 is an abundant number, since it is smaller than the sum of its proper divisors (71193972).

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

28777680 is a wasteful number, since it uses less digits than its factorization.

28777680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4466 (or 4451 counting only the distinct ones).

The product of its (nonzero) digits is 263424, while the sum is 45.

The square root of 28777680 is about 5364.4831997127. The cubic root of 28777680 is about 306.4445671844. Note that the first 3 decimals are identical.

The spelling of 28777680 in words is "twenty-eight million, seven hundred seventy-seven thousand, six hundred eighty".