28172224 has 56 divisors (see below), whose sum is σ = 59344560. Its totient is φ = 13246464.

The previous prime is 28172201. The next prime is 28172299. The reversal of 28172224 is 42227182.

It is a junction number, because it is equal to n+sod(n) for n = 28172192 and 28172201.

It is a congruent number.

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, 79632 + ... + 79984.

Almost surely, 2^28172224 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 28172224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29672280).

28172224 is an abundant number, since it is smaller than the sum of its proper divisors (31172336).

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

28172224 is a wasteful number, since it uses less digits than its factorization.

28172224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 437 (or 427 counting only the distinct ones).

The product of its digits is 3584, while the sum is 28.

The square root of 28172224 is about 5307.7513129385. The cubic root of 28172224 is about 304.2802125483.

It can be divided in two parts, 2817 and 2224, that added together give a square (5041 = 71²).

The spelling of 28172224 in words is "twenty-eight million, one hundred seventy-two thousand, two hundred twenty-four".