81982645381845 has 192 divisors, whose sum is σ = 159267424732416. Its totient is φ = 38749708247040.

The previous prime is 81982645381811. The next prime is 81982645381867. The reversal of 81982645381845 is 54818354628918.

81982645381845 is a `hidden beast` number, since 8 + 1 + 9 + 8 + 2 + 6 + 4 + 538 + 1 + 84 + 5 = 666.

It is not a de Polignac number, because 81982645381845 - 2⁶ = 81982645381781 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 2382991414 + ... + 2383025816.

It is an arithmetic number, because the mean of its divisors is an integer number (829517837148).

Almost surely, 2^{81982645381845} is an apocalyptic number.

It is an amenable number.

81982645381845 is a deficient number, since it is larger than the sum of its proper divisors (77284779350571).

81982645381845 is a wasteful number, since it uses less digits than its factorization.

81982645381845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36084 (or 36081 counting only the distinct ones).

The product of its digits is 530841600, while the sum is 72.

The spelling of 81982645381845 in words is "eighty-one trillion, nine hundred eighty-two billion, six hundred forty-five million, three hundred eighty-one thousand, eight hundred forty-five".