81003757517 has 2 divisors, whose sum is σ = 81003757518. Its totient is φ = 81003757516.

The previous prime is 81003757489. The next prime is 81003757591. The reversal of 81003757517 is 71575730018.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 72760207081 + 8243550436 = 269741^2 + 90794^2 .

It is a cyclic number.

It is not a de Polignac number, because 81003757517 - 2¹⁶ = 81003691981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81093757517) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40501878758 + 40501878759.

It is an arithmetic number, because the mean of its divisors is an integer number (40501878759).

Almost surely, 2^81003757517 is an apocalyptic number.

It is an amenable number.

81003757517 is a deficient number, since it is larger than the sum of its proper divisors (1).

81003757517 is an equidigital number, since it uses as much as digits as its factorization.

81003757517 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 205800, while the sum is 44.

The spelling of 81003757517 in words is "eighty-one billion, three million, seven hundred fifty-seven thousand, five hundred seventeen".