172211521 has 8 divisors (see below), whose sum is σ = 177343488. Its totient is φ = 167124000.

The previous prime is 172211509. The next prime is 172211531. The reversal of 172211521 is 125112271.

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 172211521 - 2⁹ = 172211009 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 172211492 and 172211501.

It is not an unprimeable number, because it can be changed into a prime (172211531) 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, 3165 + ... + 18826.

It is an arithmetic number, because the mean of its divisors is an integer number (22167936).

Almost surely, 2^172211521 is an apocalyptic number.

It is an amenable number.

172211521 is a deficient number, since it is larger than the sum of its proper divisors (5131967).

172211521 is a wasteful number, since it uses less digits than its factorization.

172211521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22223.

The product of its digits is 280, while the sum is 22.

The square root of 172211521 is about 13122.9387333783. The cubic root of 172211521 is about 556.3576544403.

Adding to 172211521 its reverse (125112271), we get a palindrome (297323792).

The spelling of 172211521 in words is "one hundred seventy-two million, two hundred eleven thousand, five hundred twenty-one".