6447781873 has 8 divisors (see below), whose sum is σ = 6951157416. Its totient is φ = 5945462400.

The previous prime is 6447781861. The next prime is 6447781927. The reversal of 6447781873 is 3781877446.

It can be written as a sum of positive squares in 4 ways, for example, as 10608049 + 6437173824 = 3257^2 + 80232^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6447781873 - 2¹³ = 6447773681 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6447781973) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 251308 + ... + 275773.

It is an arithmetic number, because the mean of its divisors is an integer number (868894677).

Almost surely, 2^6447781873 is an apocalyptic number.

It is an amenable number.

6447781873 is a deficient number, since it is larger than the sum of its proper divisors (503375543).

6447781873 is a wasteful number, since it uses less digits than its factorization.

6447781873 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 528035.

The product of its digits is 6322176, while the sum is 55.

The square root of 6447781873 is about 80298.0813780753. The cubic root of 6447781873 is about 1861.2445781586.

The spelling of 6447781873 in words is "six billion, four hundred forty-seven million, seven hundred eighty-one thousand, eight hundred seventy-three".