81668866828475 has 48 divisors (see below), whose sum is σ = 106715716185600. Its totient is φ = 61828865953920.

The previous prime is 81668866828433. The next prime is 81668866828477. The reversal of 81668866828475 is 57482866886618.

It is not a de Polignac number, because 81668866828475 - 2²⁴ = 81668850051259 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81668866828393 and 81668866828402.

It is not an unprimeable number, because it can be changed into a prime (81668866828477) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3787443044 + ... + 3787464606.

It is an arithmetic number, because the mean of its divisors is an integer number (2223244087200).

Almost surely, 2^{81668866828475} is an apocalyptic number.

81668866828475 is a deficient number, since it is larger than the sum of its proper divisors (25046849357125).

81668866828475 is a wasteful number, since it uses less digits than its factorization.

81668866828475 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29924 (or 29919 counting only the distinct ones).

The product of its digits is 11890851840, while the sum is 83.

The spelling of 81668866828475 in words is "eighty-one trillion, six hundred sixty-eight billion, eight hundred sixty-six million, eight hundred twenty-eight thousand, four hundred seventy-five".