1216687345 has 8 divisors (see below), whose sum is σ = 1487572776. Its totient is φ = 954984576.

The previous prime is 1216687343. The next prime is 1216687369. The reversal of 1216687345 is 5437866121.

It can be written as a sum of positive squares in 4 ways, for example, as 46226401 + 1170460944 = 6799^2 + 34212^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1216687345 - 2¹ = 1216687343 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1216687343) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2295372 + ... + 2295901.

It is an arithmetic number, because the mean of its divisors is an integer number (185946597).

Almost surely, 2^1216687345 is an apocalyptic number.

It is an amenable number.

1216687345 is a deficient number, since it is larger than the sum of its proper divisors (270885431).

1216687345 is an equidigital number, since it uses as much as digits as its factorization.

1216687345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4591331.

The product of its digits is 241920, while the sum is 43.

The square root of 1216687345 is about 34881.0456408635. The cubic root of 1216687345 is about 1067.5617304385.

The spelling of 1216687345 in words is "one billion, two hundred sixteen million, six hundred eighty-seven thousand, three hundred forty-five".