6413781781 has 12 divisors (see below), whose sum is σ = 7292961900. Its totient is φ = 5629648640.

The previous prime is 6413781779. The next prime is 6413781799. The reversal of 6413781781 is 1871873146.

It can be written as a sum of positive squares in 2 ways, for example, as 3002053681 + 3411728100 = 54791^2 + 58410^2 .

It is not a de Polignac number, because 6413781781 - 2¹ = 6413781779 is a prime.

It is a super-2 number, since 2×6413781781² = 82273193468575063922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6413781701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 910396 + ... + 917413.

It is an arithmetic number, because the mean of its divisors is an integer number (607746825).

Almost surely, 2^6413781781 is an apocalyptic number.

It is an amenable number.

6413781781 is a deficient number, since it is larger than the sum of its proper divisors (879180119).

6413781781 is a wasteful number, since it uses less digits than its factorization.

6413781781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1827860 (or 1827849 counting only the distinct ones).

The product of its digits is 225792, while the sum is 46.

The square root of 6413781781 is about 80086.0898096542. The cubic root of 6413781781 is about 1857.9672729946.

The spelling of 6413781781 in words is "six billion, four hundred thirteen million, seven hundred eighty-one thousand, seven hundred eighty-one".