1216808289 has 6 divisors (see below), whose sum is σ = 1757611986. Its totient is φ = 811205520.

The previous prime is 1216808287. The next prime is 1216808309. The reversal of 1216808289 is 9828086121.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 1141899264 + 74909025 = 33792^2 + 8655^2 .

It is not a de Polignac number, because 1216808289 - 2¹ = 1216808287 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1216808287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 67600452 + ... + 67600469.

It is an arithmetic number, because the mean of its divisors is an integer number (292935331).

Almost surely, 2^1216808289 is an apocalyptic number.

It is an amenable number.

1216808289 is a deficient number, since it is larger than the sum of its proper divisors (540803697).

1216808289 is a wasteful number, since it uses less digits than its factorization.

1216808289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135200927 (or 135200924 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 45.

The square root of 1216808289 is about 34882.7792614063. The cubic root of 1216808289 is about 1067.5971026889.

The spelling of 1216808289 in words is "one billion, two hundred sixteen million, eight hundred eight thousand, two hundred eighty-nine".