71217081 has 12 divisors (see below), whose sum is σ = 110782308. Its totient is φ = 43825824.

The previous prime is 71217077. The next prime is 71217089. The reversal of 71217081 is 18071217.

It can be written as a sum of positive squares in 2 ways, for example, as 27657081 + 43560000 = 5259^2 + 6600^2 .

It is not a de Polignac number, because 71217081 - 2² = 71217077 is a prime.

It is a super-2 number, since 2×71217081² = 10143745252321122, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (71217089) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 304230 + ... + 304463.

It is an arithmetic number, because the mean of its divisors is an integer number (9231859).

Almost surely, 2^71217081 is an apocalyptic number.

It is an amenable number.

71217081 is a deficient number, since it is larger than the sum of its proper divisors (39565227).

71217081 is a wasteful number, since it uses less digits than its factorization.

71217081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 608712 (or 608709 counting only the distinct ones).

The product of its (nonzero) digits is 784, while the sum is 27.

The square root of 71217081 is about 8439.0213295145. The cubic root of 71217081 is about 414.5033609965.

Adding to 71217081 its reverse (18071217), we get a palindrome (89288298).

The spelling of 71217081 in words is "seventy-one million, two hundred seventeen thousand, eighty-one".