1216547917 has 4 divisors (see below), whose sum is σ = 1310128540. Its totient is φ = 1122967296.

The previous prime is 1216547909. The next prime is 1216547921. The reversal of 1216547917 is 7197456121.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 355360201 + 861187716 = 18851^2 + 29346^2 .

It is a cyclic number.

It is not a de Polignac number, because 1216547917 - 2³ = 1216547909 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216547417) 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 3 ways as a sum of consecutive naturals, for example, 46790292 + ... + 46790317.

It is an arithmetic number, because the mean of its divisors is an integer number (327532135).

Almost surely, 2^1216547917 is an apocalyptic number.

It is an amenable number.

1216547917 is a deficient number, since it is larger than the sum of its proper divisors (93580623).

1216547917 is an equidigital number, since it uses as much as digits as its factorization.

1216547917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93580622.

The product of its digits is 105840, while the sum is 43.

The square root of 1216547917 is about 34879.0469623240. The cubic root of 1216547917 is about 1067.5209493007.

The spelling of 1216547917 in words is "one billion, two hundred sixteen million, five hundred forty-seven thousand, nine hundred seventeen".