28191500 has 24 divisors (see below), whose sum is σ = 61571328. Its totient is φ = 11276400.

The previous prime is 28191467. The next prime is 28191517. The reversal of 28191500 is 519182.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 28191500.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27692 + ... + 28691.

It is an arithmetic number, because the mean of its divisors is an integer number (2565472).

Almost surely, 2^28191500 is an apocalyptic number.

28191500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28191500 is an abundant number, since it is smaller than the sum of its proper divisors (33379828).

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

28191500 is a wasteful number, since it uses less digits than its factorization.

28191500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56402 (or 56390 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 26.

The square root of 28191500 is about 5309.5668373230. The cubic root of 28191500 is about 304.3495949320.

The spelling of 28191500 in words is "twenty-eight million, one hundred ninety-one thousand, five hundred".