172207121 has 4 divisors (see below), whose sum is σ = 173912244. Its totient is φ = 170502000.

The previous prime is 172207117. The next prime is 172207151. The reversal of 172207121 is 121702271.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 121702271 = 1093 ⋅111347.

It can be written as a sum of positive squares in 2 ways, for example, as 102718225 + 69488896 = 10135^2 + 8336^2 .

It is a cyclic number.

It is not a de Polignac number, because 172207121 - 2² = 172207117 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (172207111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 852410 + ... + 852611.

It is an arithmetic number, because the mean of its divisors is an integer number (43478061).

Almost surely, 2^172207121 is an apocalyptic number.

It is an amenable number.

172207121 is a deficient number, since it is larger than the sum of its proper divisors (1705123).

172207121 is a wasteful number, since it uses less digits than its factorization.

172207121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1705122.

The product of its (nonzero) digits is 392, while the sum is 23.

The square root of 172207121 is about 13122.7710869313. The cubic root of 172207121 is about 556.3529160920.

Adding to 172207121 its reverse (121702271), we get a palindrome (293909392).

The spelling of 172207121 in words is "one hundred seventy-two million, two hundred seven thousand, one hundred twenty-one".