81680443241 has 4 divisors (see below), whose sum is σ = 82019366484. Its totient is φ = 81341520000.

The previous prime is 81680443223. The next prime is 81680443297. The reversal of 81680443241 is 14234408618.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 28365633241 + 53314810000 = 168421^2 + 230900^2 .

It is a cyclic number.

It is not a de Polignac number, because 81680443241 - 2⁶ = 81680443177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81680443211) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 169461260 + ... + 169461741.

It is an arithmetic number, because the mean of its divisors is an integer number (20504841621).

Almost surely, 2^81680443241 is an apocalyptic number.

It is an amenable number.

81680443241 is a deficient number, since it is larger than the sum of its proper divisors (338923243).

81680443241 is a wasteful number, since it uses less digits than its factorization.

81680443241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 338923242.

The product of its (nonzero) digits is 147456, while the sum is 41.

The spelling of 81680443241 in words is "eighty-one billion, six hundred eighty million, four hundred forty-three thousand, two hundred forty-one".