1216893449 has 2 divisors, whose sum is σ = 1216893450. Its totient is φ = 1216893448.

The previous prime is 1216893401. The next prime is 1216893451. The reversal of 1216893449 is 9443986121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1067198224 + 149695225 = 32668^2 + 12235^2 .

It is a cyclic number.

It is not a de Polignac number, because 1216893449 - 2¹² = 1216889353 is a prime.

It is a Sophie Germain prime.

Together with 1216893451, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1216893479) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 608446724 + 608446725.

It is an arithmetic number, because the mean of its divisors is an integer number (608446725).

Almost surely, 2^1216893449 is an apocalyptic number.

It is an amenable number.

1216893449 is a deficient number, since it is larger than the sum of its proper divisors (1).

1216893449 is an equidigital number, since it uses as much as digits as its factorization.

1216893449 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 373248, while the sum is 47.

The square root of 1216893449 is about 34883.9998996675. Note that the first 3 decimals coincide. The cubic root of 1216893449 is about 1067.6220078579.

The spelling of 1216893449 in words is "one billion, two hundred sixteen million, eight hundred ninety-three thousand, four hundred forty-nine".