2661216768 has 400 divisors, whose sum is σ = 9268871040. Its totient is φ = 744505344.

The previous prime is 2661216763. The next prime is 2661216821. The reversal of 2661216768 is 8676121662.

2661216768 is a `hidden beast` number, since 26 + 612 + 1 + 6 + 7 + 6 + 8 = 666.

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2661216763) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 25837005 + ... + 25837107.

Almost surely, 2^2661216768 is an apocalyptic number.

2661216768 is a gapful number since it is divisible by the number (28) 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 2661216768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4634435520).

2661216768 is an abundant number, since it is smaller than the sum of its proper divisors (6607654272).

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

2661216768 is an equidigital number, since it uses as much as digits as its factorization.

2661216768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 229 (or 204 counting only the distinct ones).

The product of its digits is 290304, while the sum is 45.

The square root of 2661216768 is about 51586.9825440488. The cubic root of 2661216768 is about 1385.7772172423. Note that the first 3 decimals are identical.

The spelling of 2661216768 in words is "two billion, six hundred sixty-one million, two hundred sixteen thousand, seven hundred sixty-eight".