865386219881 has 2 divisors, whose sum is σ = 865386219882. Its totient is φ = 865386219880.

The previous prime is 865386219839. The next prime is 865386219889. The reversal of 865386219881 is 188912683568.

865386219881 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 613623122281 + 251763097600 = 783341^2 + 501760^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-865386219881 is a prime.

It is a super-2 number, since 2×865386219881² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (865386219889) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 432693109940 + 432693109941.

It is an arithmetic number, because the mean of its divisors is an integer number (432693109941).

Almost surely, 2^865386219881 is an apocalyptic number.

It is an amenable number.

865386219881 is a deficient number, since it is larger than the sum of its proper divisors (1).

865386219881 is an equidigital number, since it uses as much as digits as its factorization.

865386219881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 39813120, while the sum is 65.

The spelling of 865386219881 in words is "eight hundred sixty-five billion, three hundred eighty-six million, two hundred nineteen thousand, eight hundred eighty-one".