81841681776 has 20 divisors (see below), whose sum is σ = 211424344712. Its totient is φ = 27280560576.

The previous prime is 81841681771. The next prime is 81841681777. The reversal of 81841681776 is 67718614818.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81841681771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 852517471 + ... + 852517566.

Almost surely, 2^81841681776 is an apocalyptic number.

It is an amenable number.

81841681776 is an abundant number, since it is smaller than the sum of its proper divisors (129582662936).

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

81841681776 is a wasteful number, since it uses less digits than its factorization.

81841681776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1705035048 (or 1705035042 counting only the distinct ones).

The product of its digits is 3612672, while the sum is 57.

The spelling of 81841681776 in words is "eighty-one billion, eight hundred forty-one million, six hundred eighty-one thousand, seven hundred seventy-six".