81796765289 has 2 divisors, whose sum is σ = 81796765290. Its totient is φ = 81796765288.

The previous prime is 81796765283. The next prime is 81796765313. The reversal of 81796765289 is 98256769718.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 78773964889 + 3022800400 = 280667^2 + 54980^2 .

It is a cyclic number.

It is not a de Polignac number, because 81796765289 - 2²⁰ = 81795716713 is a prime.

It is not a weakly prime, because it can be changed into another prime (81796765283) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40898382644 + 40898382645.

It is an arithmetic number, because the mean of its divisors is an integer number (40898382645).

Almost surely, 2^81796765289 is an apocalyptic number.

It is an amenable number.

81796765289 is a deficient number, since it is larger than the sum of its proper divisors (1).

81796765289 is an equidigital number, since it uses as much as digits as its factorization.

81796765289 is an evil number, because the sum of its binary digits is even.

The product of its digits is 91445760, while the sum is 68.

The spelling of 81796765289 in words is "eighty-one billion, seven hundred ninety-six million, seven hundred sixty-five thousand, two hundred eighty-nine".