28777728 has 144 divisors (see below), whose sum is σ = 90066816. Its totient is φ = 7987200.

The previous prime is 28777717. The next prime is 28777739. The reversal of 28777728 is 82777782.

It is an interprime number because it is at equal distance from previous prime (28777717) and next prime (28777739).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

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, 284878 + ... + 284978.

It is an arithmetic number, because the mean of its divisors is an integer number (625464).

Almost surely, 2^28777728 is an apocalyptic number.

28777728 is a gapful number since it is divisible by the number (28) 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 28777728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45033408).

28777728 is an abundant number, since it is smaller than the sum of its proper divisors (61289088).

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

28777728 is a wasteful number, since it uses less digits than its factorization.

28777728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180 (or 166 counting only the distinct ones).

The product of its digits is 614656, while the sum is 48.

The square root of 28777728 is about 5364.4876735808. The cubic root of 28777728 is about 306.4447375633. Note that the first 3 decimals are identical.

The spelling of 28777728 in words is "twenty-eight million, seven hundred seventy-seven thousand, seven hundred twenty-eight".