1216608121 has 2 divisors, whose sum is σ = 1216608122. Its totient is φ = 1216608120.

The previous prime is 1216608103. The next prime is 1216608131. The reversal of 1216608121 is 1218066121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 648262521 + 568345600 = 25461^2 + 23840^2 .

It is an emirp because it is prime and its reverse (1218066121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1216608121 - 2¹⁹ = 1216083833 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1216608121.

It is not a weakly prime, because it can be changed into another prime (1216608101) 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, 608304060 + 608304061.

It is an arithmetic number, because the mean of its divisors is an integer number (608304061).

Almost surely, 2^1216608121 is an apocalyptic number.

It is an amenable number.

1216608121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1216608121 is an equidigital number, since it uses as much as digits as its factorization.

1216608121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1152, while the sum is 28.

The square root of 1216608121 is about 34879.9099912829. The cubic root of 1216608121 is about 1067.5385586827.

The spelling of 1216608121 in words is "one billion, two hundred sixteen million, six hundred eight thousand, one hundred twenty-one".