128172 has 24 divisors (see below), whose sum is σ = 326592. Its totient is φ = 38800.

The previous prime is 128159. The next prime is 128173. The reversal of 128172 is 271821.

It is a super-3 number, since 3×128172³ = 6316852528033344, which contains 333 as substring.

It is a nialpdrome in base 11 and base 12.

It is not an unprimeable number, because it can be changed into a prime (128173) 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, 354 + ... + 617.

It is an arithmetic number, because the mean of its divisors is an integer number (13608).

2¹²⁸¹⁷² is an apocalyptic number.

128172 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

128172 is an abundant number, since it is smaller than the sum of its proper divisors (198420).

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

128172 is a wasteful number, since it uses less digits than its factorization.

128172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 989 (or 987 counting only the distinct ones).

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

The square root of 128172 is about 358.0111730100. The cubic root of 128172 is about 50.4194054777.

Adding to 128172 its reverse (271821), we get a palindrome (399993).

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

The spelling of 128172 in words is "one hundred twenty-eight thousand, one hundred seventy-two".