71566617505 has 4 divisors (see below), whose sum is σ = 85879941012. Its totient is φ = 57253294000.

The previous prime is 71566617469. The next prime is 71566617523. The reversal of 71566617505 is 50571666517.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50571666517 = 6091 ⋅8302687.

It can be written as a sum of positive squares in 2 ways, for example, as 8268083041 + 63298534464 = 90929^2 + 251592^2 .

It is not a de Polignac number, because 71566617505 - 2³³ = 62976682913 is a prime.

It is a super-2 number, since 2×71566617505² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 7156661746 + ... + 7156661755.

It is an arithmetic number, because the mean of its divisors is an integer number (21469985253).

Almost surely, 2^71566617505 is an apocalyptic number.

It is an amenable number.

71566617505 is a deficient number, since it is larger than the sum of its proper divisors (14313323507).

71566617505 is a wasteful number, since it uses less digits than its factorization.

71566617505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14313323506.

The product of its (nonzero) digits is 1323000, while the sum is 49.

The spelling of 71566617505 in words is "seventy-one billion, five hundred sixty-six million, six hundred seventeen thousand, five hundred five".