81789765137 has 2 divisors, whose sum is σ = 81789765138. Its totient is φ = 81789765136.

The previous prime is 81789765119. The next prime is 81789765229. The reversal of 81789765137 is 73156798718.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81770833936 + 18931201 = 285956^2 + 4351^2 .

It is a cyclic number.

It is not a de Polignac number, because 81789765137 - 2¹⁴ = 81789748753 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81789765137.

It is not a weakly prime, because it can be changed into another prime (81789725137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40894882568 + 40894882569.

It is an arithmetic number, because the mean of its divisors is an integer number (40894882569).

Almost surely, 2^81789765137 is an apocalyptic number.

It is an amenable number.

81789765137 is a deficient number, since it is larger than the sum of its proper divisors (1).

81789765137 is an equidigital number, since it uses as much as digits as its factorization.

81789765137 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17781120, while the sum is 62.

The spelling of 81789765137 in words is "eighty-one billion, seven hundred eighty-nine million, seven hundred sixty-five thousand, one hundred thirty-seven".