217896121 has 2 divisors, whose sum is σ = 217896122. Its totient is φ = 217896120.

The previous prime is 217896109. The next prime is 217896143. The reversal of 217896121 is 121698712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 184960000 + 32936121 = 13600^2 + 5739^2 .

It is a cyclic number.

It is not a de Polignac number, because 217896121 - 2⁹ = 217895609 is a prime.

It is not a weakly prime, because it can be changed into another prime (217890121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108948060 + 108948061.

It is an arithmetic number, because the mean of its divisors is an integer number (108948061).

Almost surely, 2^217896121 is an apocalyptic number.

It is an amenable number.

217896121 is a deficient number, since it is larger than the sum of its proper divisors (1).

217896121 is an equidigital number, since it uses as much as digits as its factorization.

217896121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12096, while the sum is 37.

The square root of 217896121 is about 14761.3048542465. The cubic root of 217896121 is about 601.7505552195.

The spelling of 217896121 in words is "two hundred seventeen million, eight hundred ninety-six thousand, one hundred twenty-one".