217121242 has 32 divisors (see below), whose sum is σ = 369452160. Its totient is φ = 94944960.

The previous prime is 217121221. The next prime is 217121243. The reversal of 217121242 is 242121712.

It is not an unprimeable number, because it can be changed into a prime (217121243) 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 15 ways as a sum of consecutive naturals, for example, 63517 + ... + 66847.

It is an arithmetic number, because the mean of its divisors is an integer number (11545380).

Almost surely, 2^217121242 is an apocalyptic number.

217121242 is a deficient number, since it is larger than the sum of its proper divisors (152330918).

217121242 is a wasteful number, since it uses less digits than its factorization.

217121242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3478.

The product of its digits is 448, while the sum is 22.

The square root of 217121242 is about 14735.0345096304. The cubic root of 217121242 is about 601.0363958125.

Adding to 217121242 its reverse (242121712), we get a palindrome (459242954).

The spelling of 217121242 in words is "two hundred seventeen million, one hundred twenty-one thousand, two hundred forty-two".