171121721 has 8 divisors (see below), whose sum is σ = 177336000. Its totient is φ = 164928400.

The previous prime is 171121693. The next prime is 171121723. The reversal of 171121721 is 127121171.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 171121721 - 2²² = 166927417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (171121723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12446 + ... + 22296.

It is an arithmetic number, because the mean of its divisors is an integer number (22167000).

Almost surely, 2^171121721 is an apocalyptic number.

It is an amenable number.

171121721 is a deficient number, since it is larger than the sum of its proper divisors (6214279).

171121721 is an equidigital number, since it uses as much as digits as its factorization.

171121721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10479.

The product of its digits is 196, while the sum is 23.

The square root of 171121721 is about 13081.3501214515. The cubic root of 171121721 is about 555.1815773594.

Adding to 171121721 its reverse (127121171), we get a palindrome (298242892).

It can be divided in two parts, 1711 and 21721, that added together give a palindrome (23432).

The spelling of 171121721 in words is "one hundred seventy-one million, one hundred twenty-one thousand, seven hundred twenty-one".