8371711981 has 2 divisors, whose sum is σ = 8371711982. Its totient is φ = 8371711980.

The previous prime is 8371711979. The next prime is 8371711991. The reversal of 8371711981 is 1891171738.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7463232100 + 908479881 = 86390^2 + 30141^2 .

It is a cyclic number.

It is not a de Polignac number, because 8371711981 - 2¹ = 8371711979 is a prime.

It is a super-2 number, since 2×8371711981² (a number of 21 digits) contains 22 as substring.

Together with 8371711979, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8371711921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4185855990 + 4185855991.

It is an arithmetic number, because the mean of its divisors is an integer number (4185855991).

Almost surely, 2^8371711981 is an apocalyptic number.

It is an amenable number.

8371711981 is a deficient number, since it is larger than the sum of its proper divisors (1).

8371711981 is an equidigital number, since it uses as much as digits as its factorization.

8371711981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 84672, while the sum is 46.

The square root of 8371711981 is about 91497.0599582304. The cubic root of 8371711981 is about 2030.5082552904.

The spelling of 8371711981 in words is "eight billion, three hundred seventy-one million, seven hundred eleven thousand, nine hundred eighty-one".