866123855561512 has 16 divisors (see below), whose sum is σ = 1623982618516500. Its totient is φ = 433061823957120.

The previous prime is 866123855561509. The next prime is 866123855561519. The reversal of 866123855561512 is 215165558321668.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 776539258534116 + 89584597027396 = 27866454^2 + 9464914^2 .

It is a super-2 number, since 2×866123855561512² (a number of 31 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (866123855561519) 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 in 3 ways as a sum of consecutive naturals, for example, 31405212 + ... + 52139572.

Almost surely, 2^{866123855561512} is an apocalyptic number.

It is an amenable number.

866123855561512 is a deficient number, since it is larger than the sum of its proper divisors (757858762954988).

866123855561512 is a wasteful number, since it uses less digits than its factorization.

866123855561512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25955916 (or 25955912 counting only the distinct ones).

The product of its digits is 103680000, while the sum is 64.

The spelling of 866123855561512 in words is "eight hundred sixty-six trillion, one hundred twenty-three billion, eight hundred fifty-five million, five hundred sixty-one thousand, five hundred twelve".