28720208 has 80 divisors (see below), whose sum is σ = 66692160. Its totient is φ = 11827200.

The previous prime is 28720207. The next prime is 28720247. The reversal of 28720208 is 80202782.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28720207) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 86603 + ... + 86933.

It is an arithmetic number, because the mean of its divisors is an integer number (833652).

Almost surely, 2^28720208 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28720208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33346080).

28720208 is an abundant number, since it is smaller than the sum of its proper divisors (37971952).

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

28720208 is a wasteful number, since it uses less digits than its factorization.

28720208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 396 (or 390 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 29.

The square root of 28720208 is about 5359.1238089822. The cubic root of 28720208 is about 306.2404307436.

The spelling of 28720208 in words is "twenty-eight million, seven hundred twenty thousand, two hundred eight".