81858040705256 has 16 divisors (see below), whose sum is σ = 153486354423300. Its totient is φ = 40928346192384.

The previous prime is 81858040705139. The next prime is 81858040705291. The reversal of 81858040705256 is 65250704085818.

It can be written as a sum of positive squares in 2 ways, for example, as 76331150032900 + 5526890672356 = 8736770^2 + 2350934^2 .

It is a junction number, because it is equal to n+sod(n) for n = 81858040705195 and 81858040705204.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 83753801 + ... + 84725528.

Almost surely, 2^{81858040705256} is an apocalyptic number.

It is an amenable number.

81858040705256 is a deficient number, since it is larger than the sum of its proper divisors (71628313718044).

81858040705256 is a wasteful number, since it uses less digits than its factorization.

81858040705256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 168540068 (or 168540064 counting only the distinct ones).

The product of its (nonzero) digits is 21504000, while the sum is 59.

The spelling of 81858040705256 in words is "eighty-one trillion, eight hundred fifty-eight billion, forty million, seven hundred five thousand, two hundred fifty-six".