172920 has 64 divisors (see below), whose sum is σ = 570240. Its totient is φ = 41600.

The previous prime is 172883. The next prime is 172933. The reversal of 172920 is 29271.

It is a happy number.

172920 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (21) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1255 + ... + 1385.

It is an arithmetic number, because the mean of its divisors is an integer number (8910).

2¹⁷²⁹²⁰ is an apocalyptic number.

172920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 172920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (285120).

172920 is an abundant number, since it is smaller than the sum of its proper divisors (397320).

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

172920 is a wasteful number, since it uses less digits than its factorization.

172920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156 (or 152 counting only the distinct ones).

The product of its (nonzero) digits is 252, while the sum is 21.

The square root of 172920 is about 415.8365063339. The cubic root of 172920 is about 55.7119563223.

The spelling of 172920 in words is "one hundred seventy-two thousand, nine hundred twenty".