172721001 has 8 divisors (see below), whose sum is σ = 242415520. Its totient is φ = 109086912.

The previous prime is 172720991. The next prime is 172721023. The reversal of 172721001 is 100127271.

It is a happy number.

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

It is not a de Polignac number, because 172721001 - 2¹⁰ = 172719977 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (172721041) 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, 1515040 + ... + 1515153.

It is an arithmetic number, because the mean of its divisors is an integer number (30301940).

Almost surely, 2^172721001 is an apocalyptic number.

It is an amenable number.

172721001 is a deficient number, since it is larger than the sum of its proper divisors (69694519).

172721001 is a wasteful number, since it uses less digits than its factorization.

172721001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3030215.

The product of its (nonzero) digits is 196, while the sum is 21.

The square root of 172721001 is about 13142.3362078437. The cubic root of 172721001 is about 556.9057672629.

Adding to 172721001 its reverse (100127271), we get a palindrome (272848272).

The spelling of 172721001 in words is "one hundred seventy-two million, seven hundred twenty-one thousand, one".