81618312606856 has 32 divisors (see below), whose sum is σ = 162250406783640. Its totient is φ = 38357879712768.

The previous prime is 81618312606799. The next prime is 81618312606877. The reversal of 81618312606856 is 65860621381618.

It can be written as a sum of positive squares in 4 ways, for example, as 81587248544356 + 31064062500 = 9032566^2 + 176250^2 .

It is a junction number, because it is equal to n+sod(n) for n = 81618312606794 and 81618312606803.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 396287175 + ... + 396493078.

Almost surely, 2^{81618312606856} is an apocalyptic number.

It is an amenable number.

81618312606856 is a deficient number, since it is larger than the sum of its proper divisors (80632094176784).

81618312606856 is a wasteful number, since it uses less digits than its factorization.

81618312606856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 792781033 (or 792781029 counting only the distinct ones).

The product of its (nonzero) digits is 19906560, while the sum is 61.

The spelling of 81618312606856 in words is "eighty-one trillion, six hundred eighteen billion, three hundred twelve million, six hundred six thousand, eight hundred fifty-six".