861633825218 has 8 divisors (see below), whose sum is σ = 1297255388220. Its totient is φ = 429215362480.

The previous prime is 861633825113. The next prime is 861633825229. The reversal of 861633825218 is 812528336168.

It can be written as a sum of positive squares in 2 ways, for example, as 589205154409 + 272428670809 = 767597^2 + 521947^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 861633825218.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 800774393 + ... + 800775468.

Almost surely, 2^861633825218 is an apocalyptic number.

861633825218 is a deficient number, since it is larger than the sum of its proper divisors (435621563002).

861633825218 is a wasteful number, since it uses less digits than its factorization.

861633825218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1601550132.

The product of its digits is 3317760, while the sum is 53.

The spelling of 861633825218 in words is "eight hundred sixty-one billion, six hundred thirty-three million, eight hundred twenty-five thousand, two hundred eighteen".