81970984637579 has 2 divisors, whose sum is σ = 81970984637580. Its totient is φ = 81970984637578.

The previous prime is 81970984637557. The next prime is 81970984637617. The reversal of 81970984637579 is 97573648907918.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81970984637579 is a prime.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 81970984637497 and 81970984637506.

It is not a weakly prime, because it can be changed into another prime (81970984637539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40985492318789 + 40985492318790.

It is an arithmetic number, because the mean of its divisors is an integer number (40985492318790).

Almost surely, 2^{81970984637579} is an apocalyptic number.

81970984637579 is a deficient number, since it is larger than the sum of its proper divisors (1).

81970984637579 is an equidigital number, since it uses as much as digits as its factorization.

81970984637579 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5761082880, while the sum is 83.

The spelling of 81970984637579 in words is "eighty-one trillion, nine hundred seventy billion, nine hundred eighty-four million, six hundred thirty-seven thousand, five hundred seventy-nine".