81773828205678 has 96 divisors (see below), whose sum is σ = 211160228348160. Its totient is φ = 23233425877440.

The previous prime is 81773828205581. The next prime is 81773828205697. The reversal of 81773828205678 is 87650282837718.

81773828205678 is a `hidden beast` number, since 8 + 1 + 7 + 7 + 38 + 2 + 8 + 20 + 567 + 8 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 66533463 + ... + 67751378.

It is an arithmetic number, because the mean of its divisors is an integer number (2199585711960).

Almost surely, 2^{81773828205678} is an apocalyptic number.

81773828205678 is an abundant number, since it is smaller than the sum of its proper divisors (129386400142482).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81773828205678 is a wasteful number, since it uses less digits than its factorization.

81773828205678 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134285044 (or 134285032 counting only the distinct ones).

The product of its (nonzero) digits is 505774080, while the sum is 72.

The spelling of 81773828205678 in words is "eighty-one trillion, seven hundred seventy-three billion, eight hundred twenty-eight million, two hundred five thousand, six hundred seventy-eight".