8717981 has 2 divisors, whose sum is σ = 8717982. Its totient is φ = 8717980.

The previous prime is 8717963. The next prime is 8717987. The reversal of 8717981 is 1897178.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7474756 + 1243225 = 2734^2 + 1115^2 .

It is a cyclic number.

It is not a de Polignac number, because 8717981 - 2¹⁰ = 8716957 is a prime.

It is a super-2 number, since 2×8717981² = 152006385432722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8717987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4358990 + 4358991.

It is an arithmetic number, because the mean of its divisors is an integer number (4358991).

Almost surely, 2^8717981 is an apocalyptic number.

It is an amenable number.

8717981 is a deficient number, since it is larger than the sum of its proper divisors (1).

8717981 is an equidigital number, since it uses as much as digits as its factorization.

8717981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28224, while the sum is 41.

The square root of 8717981 is about 2952.6227324194. The cubic root of 8717981 is about 205.8126064716.

The spelling of 8717981 in words is "eight million, seven hundred seventeen thousand, nine hundred eighty-one".