172721401 has 4 divisors (see below), whose sum is σ = 174502132. Its totient is φ = 170940672.

The previous prime is 172721389. The next prime is 172721441. The reversal of 172721401 is 104127271.

172721401 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 34047225 + 138674176 = 5835^2 + 11776^2 .

It is a cyclic number.

It is not a de Polignac number, because 172721401 - 2¹¹ = 172719353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (172721441) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 890220 + ... + 890413.

It is an arithmetic number, because the mean of its divisors is an integer number (43625533).

Almost surely, 2^172721401 is an apocalyptic number.

It is an amenable number.

172721401 is a deficient number, since it is larger than the sum of its proper divisors (1780731).

172721401 is an equidigital number, since it uses as much as digits as its factorization.

172721401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1780730.

The product of its (nonzero) digits is 784, while the sum is 25.

The square root of 172721401 is about 13142.3514258294. The cubic root of 172721401 is about 556.9061971704.

Adding to 172721401 its reverse (104127271), we get a palindrome (276848672).

The spelling of 172721401 in words is "one hundred seventy-two million, seven hundred twenty-one thousand, four hundred one".