71665986 has 64 divisors (see below), whose sum is σ = 178053120. Its totient is φ = 18766080.

The previous prime is 71665981. The next prime is 71665987. The reversal of 71665986 is 68956617.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (71665981) 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, 23290 + ... + 26186.

It is an arithmetic number, because the mean of its divisors is an integer number (2782080).

Almost surely, 2^71665986 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 71665986, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89026560).

71665986 is an abundant number, since it is smaller than the sum of its proper divisors (106387134).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

71665986 is a wasteful number, since it uses less digits than its factorization.

71665986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2959.

The product of its digits is 544320, while the sum is 48.

The square root of 71665986 is about 8465.5765308690. The cubic root of 71665986 is about 415.3724550993.

The spelling of 71665986 in words is "seventy-one million, six hundred sixty-five thousand, nine hundred eighty-six".