7781216256 has 312 divisors, whose sum is σ = 25351472640. Its totient is φ = 2278195200.

The previous prime is 7781216237. The next prime is 7781216257. The reversal of 7781216256 is 6526121877.

7781216256 is a `hidden beast` number, since 7 + 7 + 8 + 12 + 1 + 625 + 6 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7781216257) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12570315 + ... + 12570933.

It is an arithmetic number, because the mean of its divisors is an integer number (81254720).

Almost surely, 2^7781216256 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 7781216256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12675736320).

7781216256 is an abundant number, since it is smaller than the sum of its proper divisors (17570256384).

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

7781216256 is a wasteful number, since it uses less digits than its factorization.

7781216256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 691 (or 666 counting only the distinct ones).

The product of its digits is 282240, while the sum is 45.

The square root of 7781216256 is about 88211.2025538707. The cubic root of 7781216256 is about 1981.5992466607.

The spelling of 7781216256 in words is "seven billion, seven hundred eighty-one million, two hundred sixteen thousand, two hundred fifty-six".