172161 has 24 divisors (see below), whose sum is σ = 284544. Its totient is φ = 99360.

The previous prime is 172157. The next prime is 172169. The reversal of 172161 is 161271.

It is not a de Polignac number, because 172161 - 2² = 172157 is a prime.

It is an Ulam number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 172161.

It is not an unprimeable number, because it can be changed into a prime (172169) 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 23 ways as a sum of consecutive naturals, for example, 3640 + ... + 3686.

It is an arithmetic number, because the mean of its divisors is an integer number (11856).

2¹⁷²¹⁶¹ is an apocalyptic number.

172161 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

172161 is a deficient number, since it is larger than the sum of its proper divisors (112383).

172161 is a wasteful number, since it uses less digits than its factorization.

172161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101 (or 98 counting only the distinct ones).

The product of its digits is 84, while the sum is 18.

The square root of 172161 is about 414.9228844014. The cubic root of 172161 is about 55.6303243651.

It can be divided in two parts, 172 and 161, that added together give a palindrome (333).

The spelling of 172161 in words is "one hundred seventy-two thousand, one hundred sixty-one".