81434776666818 has 32 divisors (see below), whose sum is σ = 167272465435776. Its totient is φ = 26411115927168.

The previous prime is 81434776666787. The next prime is 81434776666823. The reversal of 81434776666818 is 81866667743418.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 81434776666818.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37955355 + ... + 40043457.

It is an arithmetic number, because the mean of its divisors is an integer number (5227264544868).

Almost surely, 2^{81434776666818} is an apocalyptic number.

81434776666818 is an abundant number, since it is smaller than the sum of its proper divisors (85837688768958).

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

81434776666818 is a wasteful number, since it uses less digits than its factorization.

81434776666818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2263818.

The product of its digits is 1560674304, while the sum is 75.

The spelling of 81434776666818 in words is "eighty-one trillion, four hundred thirty-four billion, seven hundred seventy-six million, six hundred sixty-six thousand, eight hundred eighteen".