1216331116 has 72 divisors (see below), whose sum is σ = 2909054736. Its totient is φ = 437431680.

The previous prime is 1216331111. The next prime is 1216331117. The reversal of 1216331116 is 6111336121.

It is a super-2 number, since 2×1216331116² = 2958922767499610912, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1216331111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6330 + ... + 49726.

It is an arithmetic number, because the mean of its divisors is an integer number (40403538).

Almost surely, 2^1216331116 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1216331116, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1454527368).

1216331116 is an abundant number, since it is smaller than the sum of its proper divisors (1692723620).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1216331116 is a wasteful number, since it uses less digits than its factorization.

1216331116 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43439 (or 43430 counting only the distinct ones).

The product of its digits is 648, while the sum is 25.

The square root of 1216331116 is about 34875.9389264289. The cubic root of 1216331116 is about 1067.4575312317.

Adding to 1216331116 its reverse (6111336121), we get a palindrome (7327667237).

The spelling of 1216331116 in words is "one billion, two hundred sixteen million, three hundred thirty-one thousand, one hundred sixteen".