172381 has 4 divisors (see below), whose sum is σ = 188064. Its totient is φ = 156700.

The previous prime is 172373. The next prime is 172399. The reversal of 172381 is 183271.

172381 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is the 170-th star number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 183271 = 11 ⋅16661.

It is a cyclic number.

It is not a de Polignac number, because 172381 - 2³ = 172373 is a prime.

It is a super-2 number, since 2×172381² = 59430418322, which contains 22 as substring.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

172381 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172321) 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, 7825 + ... + 7846.

It is an arithmetic number, because the mean of its divisors is an integer number (47016).

2¹⁷²³⁸¹ is an apocalyptic number.

172381 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

172381 is a deficient number, since it is larger than the sum of its proper divisors (15683).

172381 is a wasteful number, since it uses less digits than its factorization.

172381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15682.

The product of its digits is 336, while the sum is 22.

The square root of 172381 is about 415.1879092652. The cubic root of 172381 is about 55.6540104534.

The spelling of 172381 in words is "one hundred seventy-two thousand, three hundred eighty-one".