71661687285 has 32 divisors (see below), whose sum is σ = 118986848640. Its totient is φ = 36785170688.

The previous prime is 71661687217. The next prime is 71661687289. The reversal of 71661687285 is 58278616617.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 71661687285 - 2⁷ = 71661687157 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71661687289) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 121947 + ... + 397736.

It is an arithmetic number, because the mean of its divisors is an integer number (3718339020).

Almost surely, 2^71661687285 is an apocalyptic number.

It is an amenable number.

71661687285 is a deficient number, since it is larger than the sum of its proper divisors (47325161355).

71661687285 is a wasteful number, since it uses less digits than its factorization.

71661687285 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 520037.

The product of its digits is 6773760, while the sum is 57.

The spelling of 71661687285 in words is "seventy-one billion, six hundred sixty-one million, six hundred eighty-seven thousand, two hundred eighty-five".