28188720 has 360 divisors, whose sum is σ = 119081664. Its totient is φ = 5935104.

The previous prime is 28188697. The next prime is 28188757. The reversal of 28188720 is 2788182.

It is a tau number, because it is divible by the number of its divisors (360).

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 599737 + ... + 599783.

Almost surely, 2^28188720 is an apocalyptic number.

28188720 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 28188720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (59540832).

28188720 is an abundant number, since it is smaller than the sum of its proper divisors (90892944).

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

28188720 is a wasteful number, since it uses less digits than its factorization.

28188720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97 (or 81 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 36.

The square root of 28188720 is about 5309.3050392683. The cubic root of 28188720 is about 304.3395905018.

The spelling of 28188720 in words is "twenty-eight million, one hundred eighty-eight thousand, seven hundred twenty".