2561216112 has 560 divisors, whose sum is σ = 9714933760. Its totient is φ = 634894848.

The previous prime is 2561216081. The next prime is 2561216159. The reversal of 2561216112 is 2116121652.

2561216112 is a `hidden beast` number, since 25 + 6 + 1 + 21 + 611 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

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 111 ways as a sum of consecutive naturals, for example, 20166993 + ... + 20167119.

It is an arithmetic number, because the mean of its divisors is an integer number (17348096).

Almost surely, 2^2561216112 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 2561216112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4857466880).

2561216112 is an abundant number, since it is smaller than the sum of its proper divisors (7153717648).

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

2561216112 is a wasteful number, since it uses less digits than its factorization.

2561216112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192 (or 171 counting only the distinct ones).

The product of its digits is 1440, while the sum is 27.

The square root of 2561216112 is about 50608.4588976981. The cubic root of 2561216112 is about 1368.1973399525.

Adding to 2561216112 its reverse (2116121652), we get a palindrome (4677337764).

The spelling of 2561216112 in words is "two billion, five hundred sixty-one million, two hundred sixteen thousand, one hundred twelve".