71261681 has 2 divisors, whose sum is σ = 71261682. Its totient is φ = 71261680.

The previous prime is 71261633. The next prime is 71261711. The reversal of 71261681 is 18616217.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 70291456 + 970225 = 8384^2 + 985^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71261681 is a prime.

It is a super-2 number, since 2×71261681² = 10156454357891522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (71261611) 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 as a sum of consecutive naturals, namely, 35630840 + 35630841.

It is an arithmetic number, because the mean of its divisors is an integer number (35630841).

Almost surely, 2^71261681 is an apocalyptic number.

It is an amenable number.

71261681 is a deficient number, since it is larger than the sum of its proper divisors (1).

71261681 is an equidigital number, since it uses as much as digits as its factorization.

71261681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4032, while the sum is 32.

The square root of 71261681 is about 8441.6634024344. The cubic root of 71261681 is about 414.5898711044.

Adding to 71261681 its reverse (18616217), we get a palindrome (89877898).

The spelling of 71261681 in words is "seventy-one million, two hundred sixty-one thousand, six hundred eighty-one".