81071686684039 has 4 divisors (see below), whose sum is σ = 81071704793800. Its totient is φ = 81071668574280.

The previous prime is 81071686684019. The next prime is 81071686684133. The reversal of 81071686684039 is 93048668617018.

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

It is a cyclic number.

It is not a de Polignac number, because 81071686684039 - 2¹¹ = 81071686681991 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81071686684019) 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, 3089344 + ... + 13102954.

It is an arithmetic number, because the mean of its divisors is an integer number (20267926198450).

Almost surely, 2^{81071686684039} is an apocalyptic number.

81071686684039 is a deficient number, since it is larger than the sum of its proper divisors (18109761).

81071686684039 is a wasteful number, since it uses less digits than its factorization.

81071686684039 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18109760.

The product of its (nonzero) digits is 83607552, while the sum is 67.

The spelling of 81071686684039 in words is "eighty-one trillion, seventy-one billion, six hundred eighty-six million, six hundred eighty-four thousand, thirty-nine".