81717505063 has 2 divisors, whose sum is σ = 81717505064. Its totient is φ = 81717505062.

The previous prime is 81717505049. The next prime is 81717505073. The reversal of 81717505063 is 36050571718.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81717505063 - 2⁵ = 81717505031 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81717505073) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40858752531 + 40858752532.

It is an arithmetic number, because the mean of its divisors is an integer number (40858752532).

Almost surely, 2^81717505063 is an apocalyptic number.

81717505063 is a deficient number, since it is larger than the sum of its proper divisors (1).

81717505063 is an equidigital number, since it uses as much as digits as its factorization.

81717505063 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 176400, while the sum is 43.

The spelling of 81717505063 in words is "eighty-one billion, seven hundred seventeen million, five hundred five thousand, sixty-three".