1216756656 has 120 divisors (see below), whose sum is σ = 3607269120. Its totient is φ = 381794688.

The previous prime is 1216756591. The next prime is 1216756663. The reversal of 1216756656 is 6566576121.

1216756656 is a `hidden beast` number, since 1 + 21 + 67 + 566 + 5 + 6 = 666.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 455581 + ... + 458243.

It is an arithmetic number, because the mean of its divisors is an integer number (30060576).

Almost surely, 2^1216756656 is an apocalyptic number.

1216756656 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1216756656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1803634560).

1216756656 is an abundant number, since it is smaller than the sum of its proper divisors (2390512464).

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

1216756656 is a wasteful number, since it uses less digits than its factorization.

1216756656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2863 (or 2854 counting only the distinct ones).

The product of its digits is 453600, while the sum is 45.

The square root of 1216756656 is about 34882.0391605766. The cubic root of 1216756656 is about 1067.5820019751.

The spelling of 1216756656 in words is "one billion, two hundred sixteen million, seven hundred fifty-six thousand, six hundred fifty-six".