81501713217 has 16 divisors (see below), whose sum is σ = 120983345280. Its totient is φ = 54226445616.

The previous prime is 81501713173. The next prime is 81501713221. The reversal of 81501713217 is 71231710518.

81501713217 is a `hidden beast` number, since 8 + 1 + 501 + 7 + 132 + 17 = 666.

It is not a de Polignac number, because 81501713217 - 2¹¹ = 81501711169 is a prime.

It is a super-2 number, since 2×81501713217² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81501713617) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2986998 + ... + 3014159.

It is an arithmetic number, because the mean of its divisors is an integer number (7561459080).

Almost surely, 2^81501713217 is an apocalyptic number.

It is an amenable number.

81501713217 is a deficient number, since it is larger than the sum of its proper divisors (39481632063).

81501713217 is a wasteful number, since it uses less digits than its factorization.

81501713217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6001669 (or 6001663 counting only the distinct ones).

The product of its (nonzero) digits is 11760, while the sum is 36.

The spelling of 81501713217 in words is "eighty-one billion, five hundred one million, seven hundred thirteen thousand, two hundred seventeen".