1216658856 has 128 divisors (see below), whose sum is σ = 3766625280. Its totient is φ = 319527936.

The previous prime is 1216658851. The next prime is 1216658867. The reversal of 1216658856 is 6588566121.

It is not an unprimeable number, because it can be changed into a prime (1216658851) 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 31 ways as a sum of consecutive naturals, for example, 117855 + ... + 127761.

It is an arithmetic number, because the mean of its divisors is an integer number (29426760).

Almost surely, 2^1216658856 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 1216658856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1883312640).

1216658856 is an abundant number, since it is smaller than the sum of its proper divisors (2549966424).

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

1216658856 is a wasteful number, since it uses less digits than its factorization.

1216658856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9983 (or 9979 counting only the distinct ones).

The product of its digits is 691200, while the sum is 48.

The square root of 1216658856 is about 34880.6372648207. The cubic root of 1216658856 is about 1067.5533979765.

The spelling of 1216658856 in words is "one billion, two hundred sixteen million, six hundred fifty-eight thousand, eight hundred fifty-six".