856685874893 has 2 divisors, whose sum is σ = 856685874894. Its totient is φ = 856685874892.

The previous prime is 856685874791. The next prime is 856685874907. The reversal of 856685874893 is 398478586658.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 459681288004 + 397004586889 = 677998^2 + 630083^2 .

It is a cyclic number.

It is not a de Polignac number, because 856685874893 - 2⁸ = 856685874637 is a prime.

It is a super-2 number, since 2×856685874893² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (856685874193) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 428342937446 + 428342937447.

It is an arithmetic number, because the mean of its divisors is an integer number (428342937447).

Almost surely, 2^856685874893 is an apocalyptic number.

It is an amenable number.

856685874893 is a deficient number, since it is larger than the sum of its proper divisors (1).

856685874893 is an equidigital number, since it uses as much as digits as its factorization.

856685874893 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2786918400, while the sum is 77.

The spelling of 856685874893 in words is "eight hundred fifty-six billion, six hundred eighty-five million, eight hundred seventy-four thousand, eight hundred ninety-three".