172121245 has 4 divisors (see below), whose sum is σ = 206545500. Its totient is φ = 137696992.

The previous prime is 172121233. The next prime is 172121249. The reversal of 172121245 is 542121271.

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 34082244 + 138039001 = 5838^2 + 11749^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-172121245 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172121249) 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 3 ways as a sum of consecutive naturals, for example, 17212120 + ... + 17212129.

It is an arithmetic number, because the mean of its divisors is an integer number (51636375).

Almost surely, 2^172121245 is an apocalyptic number.

It is an amenable number.

172121245 is a deficient number, since it is larger than the sum of its proper divisors (34424255).

172121245 is an equidigital number, since it uses as much as digits as its factorization.

172121245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34424254.

The product of its digits is 1120, while the sum is 25.

The square root of 172121245 is about 13119.4986565798. The cubic root of 172121245 is about 556.2604202904.

The spelling of 172121245 in words is "one hundred seventy-two million, one hundred twenty-one thousand, two hundred forty-five".