1216064556 has 288 divisors, whose sum is σ = 3903943680. Its totient is φ = 325721088.

The previous prime is 1216064527. The next prime is 1216064611. The reversal of 1216064556 is 6554606121.

1216064556 is a `hidden beast` number, since 1 + 2 + 1 + 6 + 0 + 645 + 5 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 1216064556.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 11806401 + ... + 11806503.

It is an arithmetic number, because the mean of its divisors is an integer number (13555360).

Almost surely, 2^1216064556 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 1216064556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1951971840).

1216064556 is an abundant number, since it is smaller than the sum of its proper divisors (2687879124).

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

1216064556 is a wasteful number, since it uses less digits than its factorization.

1216064556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 250 (or 235 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The square root of 1216064556 is about 34872.1171711727. The cubic root of 1216064556 is about 1067.3795474590.

The spelling of 1216064556 in words is "one billion, two hundred sixteen million, sixty-four thousand, five hundred fifty-six".