216217121 has 4 divisors (see below), whose sum is σ = 216261552. Its totient is φ = 216172692.

The previous prime is 216217117. The next prime is 216217129. The reversal of 216217121 is 121712612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 216217121 - 2² = 216217117 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216217129) 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, 13871 + ... + 24996.

It is an arithmetic number, because the mean of its divisors is an integer number (54065388).

Almost surely, 2^216217121 is an apocalyptic number.

It is an amenable number.

216217121 is a deficient number, since it is larger than the sum of its proper divisors (44431).

216217121 is an equidigital number, since it uses as much as digits as its factorization.

216217121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44430.

The product of its digits is 336, while the sum is 23.

The square root of 216217121 is about 14704.3232078188. The cubic root of 216217121 is about 600.2009706401.

Adding to 216217121 its reverse (121712612), we get a palindrome (337929733).

The spelling of 216217121 in words is "two hundred sixteen million, two hundred seventeen thousand, one hundred twenty-one".