71666691 has 8 divisors (see below), whose sum is σ = 95745360. Its totient is φ = 47682912.

The previous prime is 71666687. The next prime is 71666701. The reversal of 71666691 is 19666617.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 71666691 - 2² = 71666687 is a prime.

It is a super-2 number, since 2×71666691² = 10272229197778962, which contains 22 as substring.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (71666641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21940 + ... + 24993.

It is an arithmetic number, because the mean of its divisors is an integer number (11968170).

Almost surely, 2^71666691 is an apocalyptic number.

71666691 is a deficient number, since it is larger than the sum of its proper divisors (24078669).

71666691 is a wasteful number, since it uses less digits than its factorization.

71666691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47445.

The product of its digits is 81648, while the sum is 42.

The square root of 71666691 is about 8465.6181699862. The cubic root of 71666691 is about 415.3738171431.

The spelling of 71666691 in words is "seventy-one million, six hundred sixty-six thousand, six hundred ninety-one".