81288189643 has 2 divisors, whose sum is σ = 81288189644. Its totient is φ = 81288189642.

The previous prime is 81288189637. The next prime is 81288189761. The reversal of 81288189643 is 34698188218.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81288189643 is a prime.

It is not a weakly prime, because it can be changed into another prime (81288189613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40644094821 + 40644094822.

It is an arithmetic number, because the mean of its divisors is an integer number (40644094822).

Almost surely, 2^81288189643 is an apocalyptic number.

81288189643 is a deficient number, since it is larger than the sum of its proper divisors (1).

81288189643 is an equidigital number, since it uses as much as digits as its factorization.

81288189643 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5308416, while the sum is 58.

The spelling of 81288189643 in words is "eighty-one billion, two hundred eighty-eight million, one hundred eighty-nine thousand, six hundred forty-three".