71985004781 has 2 divisors, whose sum is σ = 71985004782. Its totient is φ = 71985004780.

The previous prime is 71985004769. The next prime is 71985004783. The reversal of 71985004781 is 18740058917.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 68243725225 + 3741279556 = 261235^2 + 61166^2 .

It is an emirp because it is prime and its reverse (18740058917) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 71985004781 - 2¹⁰ = 71985003757 is a prime.

It is a super-2 number, since 2×71985004781² (a number of 23 digits) contains 22 as substring.

Together with 71985004783, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71985004783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35992502390 + 35992502391.

It is an arithmetic number, because the mean of its divisors is an integer number (35992502391).

Almost surely, 2^71985004781 is an apocalyptic number.

It is an amenable number.

71985004781 is a deficient number, since it is larger than the sum of its proper divisors (1).

71985004781 is an equidigital number, since it uses as much as digits as its factorization.

71985004781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 564480, while the sum is 50.

The spelling of 71985004781 in words is "seventy-one billion, nine hundred eighty-five million, four thousand, seven hundred eighty-one".