172121 has 4 divisors (see below), whose sum is σ = 181200. Its totient is φ = 163044.

The previous prime is 172097. The next prime is 172127. The reversal of 172121 is 121271.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-172121 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 172096 and 172105.

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 (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4511 + ... + 4548.

It is an arithmetic number, because the mean of its divisors is an integer number (45300).

2¹⁷²¹²¹ is an apocalyptic number.

It is an amenable number.

172121 is a deficient number, since it is larger than the sum of its proper divisors (9079).

172121 is an equidigital number, since it uses as much as digits as its factorization.

172121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9078.

The product of its digits is 28, while the sum is 14.

The square root of 172121 is about 414.8746798733. The cubic root of 172121 is about 55.6260156360.

Adding to 172121 its reverse (121271), we get a palindrome (293392).

The spelling of 172121 in words is "one hundred seventy-two thousand, one hundred twenty-one", and thus it is an iban number.