865852822821 has 16 divisors (see below), whose sum is σ = 1319424755328. Its totient is φ = 494761800000.

The previous prime is 865852822799. The next prime is 865852822841. The reversal of 865852822821 is 128228258568.

It is not a de Polignac number, because 865852822821 - 2²¹ = 865850725669 is a prime.

It is a super-2 number, since 2×865852822821² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (865852822841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 527071 + ... + 1417571.

It is an arithmetic number, because the mean of its divisors is an integer number (82464047208).

Almost surely, 2^865852822821 is an apocalyptic number.

It is an amenable number.

865852822821 is a deficient number, since it is larger than the sum of its proper divisors (453571932507).

865852822821 is a wasteful number, since it uses less digits than its factorization.

865852822821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 936812.

The product of its digits is 9830400, while the sum is 57.

The spelling of 865852822821 in words is "eight hundred sixty-five billion, eight hundred fifty-two million, eight hundred twenty-two thousand, eight hundred twenty-one".