172721105 has 8 divisors (see below), whose sum is σ = 219457512. Its totient is φ = 130048768.

The previous prime is 172721093. The next prime is 172721111. The reversal of 172721105 is 501127271.

It can be written as a sum of positive squares in 4 ways, for example, as 6723649 + 165997456 = 2593^2 + 12884^2 .

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 172721105 - 2⁴ = 172721089 is a prime.

It is a super-2 number, since 2×172721105² = 59665160224842050, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

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, 1015922 + ... + 1016091.

It is an arithmetic number, because the mean of its divisors is an integer number (27432189).

Almost surely, 2^172721105 is an apocalyptic number.

It is an amenable number.

172721105 is a deficient number, since it is larger than the sum of its proper divisors (46736407).

172721105 is a wasteful number, since it uses less digits than its factorization.

172721105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2032035.

The product of its (nonzero) digits is 980, while the sum is 26.

The square root of 172721105 is about 13142.3401645217. The cubic root of 172721105 is about 556.9058790389.

Adding to 172721105 its reverse (501127271), we get a palindrome (673848376).

The spelling of 172721105 in words is "one hundred seventy-two million, seven hundred twenty-one thousand, one hundred five".