28388880 has 200 divisors, whose sum is σ = 106498392. Its totient is φ = 6967296.

The previous prime is 28388873. The next prime is 28388881. The reversal of 28388880 is 8888382.

It can be written as a sum of positive squares in 4 ways, for example, as 1296 + 28387584 = 36^2 + 5328^2 .

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

It is not an unprimeable number, because it can be changed into a prime (28388881) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 84072 + ... + 84408.

Almost surely, 2^28388880 is an apocalyptic number.

28388880 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 28388880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (53249196).

28388880 is an abundant number, since it is smaller than the sum of its proper divisors (78109512).

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

28388880 is a wasteful number, since it uses less digits than its factorization.

28388880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 375 (or 360 counting only the distinct ones).

The product of its (nonzero) digits is 196608, while the sum is 45.

The square root of 28388880 is about 5328.1216202335. The cubic root of 28388880 is about 305.0582348715.

The spelling of 28388880 in words is "twenty-eight million, three hundred eighty-eight thousand, eight hundred eighty".