6856641562543 has 2 divisors, whose sum is σ = 6856641562544. Its totient is φ = 6856641562542.

The previous prime is 6856641562541. The next prime is 6856641562651. The reversal of 6856641562543 is 3452651466586.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6856641562543 - 2¹ = 6856641562541 is a prime.

It is a super-3 number, since 3×6856641562543³ (a number of 39 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

Together with 6856641562541, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6856641562541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3428320781271 + 3428320781272.

It is an arithmetic number, because the mean of its divisors is an integer number (3428320781272).

Almost surely, 2^{6856641562543} is an apocalyptic number.

6856641562543 is a deficient number, since it is larger than the sum of its proper divisors (1).

6856641562543 is an equidigital number, since it uses as much as digits as its factorization.

6856641562543 is an evil number, because the sum of its binary digits is even.

The product of its digits is 124416000, while the sum is 61.

The spelling of 6856641562543 in words is "six trillion, eight hundred fifty-six billion, six hundred forty-one million, five hundred sixty-two thousand, five hundred forty-three".