81814768777729 has 8 divisors (see below), whose sum is σ = 88323636038120. Its totient is φ = 75336676304256.

The previous prime is 81814768777727. The next prime is 81814768777741. The reversal of 81814768777729 is 92777786741818.

It can be written as a sum of positive squares in 4 ways, for example, as 28640746407025 + 53174022370704 = 5351705^2 + 7292052^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81814768777729 - 2¹ = 81814768777727 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81814768777727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7693691202 + ... + 7693701835.

It is an arithmetic number, because the mean of its divisors is an integer number (11040454504765).

Almost surely, 2^{81814768777729} is an apocalyptic number.

It is an amenable number.

81814768777729 is a deficient number, since it is larger than the sum of its proper divisors (6508867260391).

81814768777729 is a wasteful number, since it uses less digits than its factorization.

81814768777729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15387393459.

The product of its digits is 3717439488, while the sum is 82.

The spelling of 81814768777729 in words is "eighty-one trillion, eight hundred fourteen billion, seven hundred sixty-eight million, seven hundred seventy-seven thousand, seven hundred twenty-nine".