81653709571097 has 2 divisors, whose sum is σ = 81653709571098. Its totient is φ = 81653709571096.

The previous prime is 81653709571051. The next prime is 81653709571219. The reversal of 81653709571097 is 79017590735618.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 65687523686656 + 15966185884441 = 8104784^2 + 3995771^2 .

It is a cyclic number.

It is not a de Polignac number, because 81653709571097 - 2⁶ = 81653709571033 is a prime.

It is not a weakly prime, because it can be changed into another prime (81653709561097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40826854785548 + 40826854785549.

It is an arithmetic number, because the mean of its divisors is an integer number (40826854785549).

Almost surely, 2^{81653709571097} is an apocalyptic number.

It is an amenable number.

81653709571097 is a deficient number, since it is larger than the sum of its proper divisors (1).

81653709571097 is an equidigital number, since it uses as much as digits as its factorization.

81653709571097 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 100018800, while the sum is 68.

The spelling of 81653709571097 in words is "eighty-one trillion, six hundred fifty-three billion, seven hundred nine million, five hundred seventy-one thousand, ninety-seven".