28157172 has 12 divisors (see below), whose sum is σ = 65700096. Its totient is φ = 9385720.

The previous prime is 28157159. The next prime is 28157179. The reversal of 28157172 is 27175182.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28157179) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1173204 + ... + 1173227.

It is an arithmetic number, because the mean of its divisors is an integer number (5475008).

Almost surely, 2^28157172 is an apocalyptic number.

It is an amenable number.

28157172 is an abundant number, since it is smaller than the sum of its proper divisors (37542924).

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

28157172 is a wasteful number, since it uses less digits than its factorization.

28157172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2346438 (or 2346436 counting only the distinct ones).

The product of its digits is 7840, while the sum is 33.

The square root of 28157172 is about 5306.3331972276. Note that the first 3 decimals coincide. The cubic root of 28157172 is about 304.2260120980.

The spelling of 28157172 in words is "twenty-eight million, one hundred fifty-seven thousand, one hundred seventy-two".