28172500 has 60 divisors (see below), whose sum is σ = 62979840. Its totient is φ = 11020000.

The previous prime is 28172479. The next prime is 28172513. The reversal of 28172500 is 527182.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 147405 + ... + 147595.

It is an arithmetic number, because the mean of its divisors is an integer number (1049664).

Almost surely, 2^28172500 is an apocalyptic number.

28172500 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 28172500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31489920).

28172500 is an abundant number, since it is smaller than the sum of its proper divisors (34807340).

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

28172500 is a wasteful number, since it uses less digits than its factorization.

28172500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 274 (or 257 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 25.

The square root of 28172500 is about 5307.7773125857. Note that the first 3 decimals coincide. The cubic root of 28172500 is about 304.2812062110.

Adding to 28172500 its reverse (527182), we get a palindrome (28699682).

The spelling of 28172500 in words is "twenty-eight million, one hundred seventy-two thousand, five hundred".