172128 has 48 divisors (see below), whose sum is σ = 495936. Its totient is φ = 51840.

The previous prime is 172127. The next prime is 172147. The reversal of 172128 is 821271.

It is a tau number, because it is divible by the number of its divisors (48).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 975 + ... + 1137.

It is an arithmetic number, because the mean of its divisors is an integer number (10332).

2¹⁷²¹²⁸ 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 172128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (247968).

172128 is an abundant number, since it is smaller than the sum of its proper divisors (323808).

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

172128 is a wasteful number, since it uses less digits than its factorization.

172128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 187 (or 179 counting only the distinct ones).

The product of its digits is 224, while the sum is 21.

The square root of 172128 is about 414.8831160701. The cubic root of 172128 is about 55.6267697118.

Adding to 172128 its reverse (821271), we get a palindrome (993399).

It can be divided in two parts, 172 and 128, that added together give a triangular number (300 = T₂₄).

The spelling of 172128 in words is "one hundred seventy-two thousand, one hundred twenty-eight".