81726103517 has 2 divisors, whose sum is σ = 81726103518. Its totient is φ = 81726103516.

The previous prime is 81726103507. The next prime is 81726103519. The reversal of 81726103517 is 71530162718.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 53228949796 + 28497153721 = 230714^2 + 168811^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81726103517 is a prime.

It is a super-4 number, since 4×81726103517⁴ (a number of 45 digits) contains 4444 as substring.

Together with 81726103519, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81726103519) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40863051758 + 40863051759.

It is an arithmetic number, because the mean of its divisors is an integer number (40863051759).

Almost surely, 2^81726103517 is an apocalyptic number.

It is an amenable number.

81726103517 is a deficient number, since it is larger than the sum of its proper divisors (1).

81726103517 is an equidigital number, since it uses as much as digits as its factorization.

81726103517 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 70560, while the sum is 41.

The spelling of 81726103517 in words is "eighty-one billion, seven hundred twenty-six million, one hundred three thousand, five hundred seventeen".