6436781316856 has 64 divisors (see below), whose sum is σ = 13186116852480. Its totient is φ = 2921373646080.

The previous prime is 6436781316851. The next prime is 6436781316871. The reversal of 6436781316856 is 6586131876346.

It is a super-2 number, since 2×6436781316856² (a number of 26 digits) contains 22 as substring.

Its product of digits (104509440) is a multiple of the sum of its prime divisors (30720).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6436781316851) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 241544125 + ... + 241570771.

It is an arithmetic number, because the mean of its divisors is an integer number (206033075820).

Almost surely, 2^{6436781316856} is an apocalyptic number.

It is an amenable number.

6436781316856 is an abundant number, since it is smaller than the sum of its proper divisors (6749335535624).

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

6436781316856 is a wasteful number, since it uses less digits than its factorization.

6436781316856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30724 (or 30720 counting only the distinct ones).

The product of its digits is 104509440, while the sum is 64.

The spelling of 6436781316856 in words is "six trillion, four hundred thirty-six billion, seven hundred eighty-one million, three hundred sixteen thousand, eight hundred fifty-six".