71321666566 has 16 divisors (see below), whose sum is σ = 109435345488. Its totient is φ = 34848580000.

The previous prime is 71321666543. The next prime is 71321666569. The reversal of 71321666566 is 66566612317.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71321666569) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1313725 + ... + 1366936.

It is an arithmetic number, because the mean of its divisors is an integer number (6839709093).

Almost surely, 2^71321666566 is an apocalyptic number.

71321666566 is a deficient number, since it is larger than the sum of its proper divisors (38113678922).

71321666566 is a wasteful number, since it uses less digits than its factorization.

71321666566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2680967.

The product of its digits is 1632960, while the sum is 49.

The spelling of 71321666566 in words is "seventy-one billion, three hundred twenty-one million, six hundred sixty-six thousand, five hundred sixty-six".