71661247505 has 16 divisors (see below), whose sum is σ = 88479022464. Its totient is φ = 55684302720.

The previous prime is 71661247487. The next prime is 71661247507. The reversal of 71661247505 is 50574216617.

It is not a de Polignac number, because 71661247505 - 2³² = 67366280209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71661247507) 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, 723437 + ... + 816506.

It is an arithmetic number, because the mean of its divisors is an integer number (5529938904).

Almost surely, 2^71661247505 is an apocalyptic number.

It is an amenable number.

71661247505 is a deficient number, since it is larger than the sum of its proper divisors (16817774959).

71661247505 is a wasteful number, since it uses less digits than its factorization.

71661247505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1540216.

The product of its (nonzero) digits is 352800, while the sum is 44.

The spelling of 71661247505 in words is "seventy-one billion, six hundred sixty-one million, two hundred forty-seven thousand, five hundred five".