71781868313 has 2 divisors, whose sum is σ = 71781868314. Its totient is φ = 71781868312.

The previous prime is 71781868253. The next prime is 71781868337. The reversal of 71781868313 is 31386818717.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 57990419344 + 13791448969 = 240812^2 + 117437^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71781868313 is a prime.

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 (71781868343) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35890934156 + 35890934157.

It is an arithmetic number, because the mean of its divisors is an integer number (35890934157).

Almost surely, 2^71781868313 is an apocalyptic number.

It is an amenable number.

71781868313 is a deficient number, since it is larger than the sum of its proper divisors (1).

71781868313 is an equidigital number, since it uses as much as digits as its factorization.

71781868313 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1354752, while the sum is 53.

The spelling of 71781868313 in words is "seventy-one billion, seven hundred eighty-one million, eight hundred sixty-eight thousand, three hundred thirteen".