28173729 has 8 divisors (see below), whose sum is σ = 38438752. Its totient is φ = 18345600.

The previous prime is 28173721. The next prime is 28173757. The reversal of 28173729 is 92737182.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 28173729 - 2³ = 28173721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28173721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 109072 + ... + 109329.

It is an arithmetic number, because the mean of its divisors is an integer number (4804844).

Almost surely, 2^28173729 is an apocalyptic number.

It is an amenable number.

28173729 is a deficient number, since it is larger than the sum of its proper divisors (10265023).

28173729 is a wasteful number, since it uses less digits than its factorization.

28173729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218447.

The product of its digits is 42336, while the sum is 39.

The square root of 28173729 is about 5307.8930848313. The cubic root of 28173729 is about 304.2856308115.

The spelling of 28173729 in words is "twenty-eight million, one hundred seventy-three thousand, seven hundred twenty-nine".