81965180897 has 4 divisors (see below), whose sum is σ = 82047891456. Its totient is φ = 81882470340.

The previous prime is 81965180887. The next prime is 81965180917. The reversal of 81965180897 is 79808156918.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81965180897 - 2¹² = 81965176801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81965180837) 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, 41353793 + ... + 41355774.

It is an arithmetic number, because the mean of its divisors is an integer number (20511972864).

Almost surely, 2^81965180897 is an apocalyptic number.

It is an amenable number.

81965180897 is a deficient number, since it is larger than the sum of its proper divisors (82710559).

81965180897 is an equidigital number, since it uses as much as digits as its factorization.

81965180897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82710558.

The product of its (nonzero) digits is 8709120, while the sum is 62.

The spelling of 81965180897 in words is "eighty-one billion, nine hundred sixty-five million, one hundred eighty thousand, eight hundred ninety-seven".