28509900 has 108 divisors (see below), whose sum is σ = 86187192. Its totient is φ = 7275520.

The previous prime is 28509893. The next prime is 28509911. The reversal of 28509900 is 990582.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 252244 + ... + 252356.

Almost surely, 2^28509900 is an apocalyptic number.

28509900 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 28509900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43093596).

28509900 is an abundant number, since it is smaller than the sum of its proper divisors (57677292).

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

28509900 is a wasteful number, since it uses less digits than its factorization.

28509900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 188 (or 152 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 33.

The square root of 28509900 is about 5339.4662654614. The cubic root of 28509900 is about 305.4911016790.

The spelling of 28509900 in words is "twenty-eight million, five hundred nine thousand, nine hundred".