81729266099697 has 12 divisors (see below), whose sum is σ = 118053468469300. Its totient is φ = 54486138583008.

The previous prime is 81729266099671. The next prime is 81729266099743. The reversal of 81729266099697 is 79699066292718.

It can be written as a sum of positive squares in 2 ways, for example, as 31092322450401 + 50636943649296 = 5576049^2 + 7115964^2 .

It is not a de Polignac number, because 81729266099697 - 2¹⁰ = 81729266098673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81729266099597) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 16325283 + ... + 20735799.

Almost surely, 2^{81729266099697} is an apocalyptic number.

It is an amenable number.

81729266099697 is a deficient number, since it is larger than the sum of its proper divisors (36324202369603).

81729266099697 is a wasteful number, since it uses less digits than its factorization.

81729266099697 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6469472 (or 6469469 counting only the distinct ones).

The product of its (nonzero) digits is 2222131968, while the sum is 81.

The spelling of 81729266099697 in words is "eighty-one trillion, seven hundred twenty-nine billion, two hundred sixty-six million, ninety-nine thousand, six hundred ninety-seven".