9917881 has 2 divisors, whose sum is σ = 9917882. Its totient is φ = 9917880.

The previous prime is 9917849. The next prime is 9917891. The reversal of 9917881 is 1887199.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6150400 + 3767481 = 2480^2 + 1941^2 .

It is an emirp because it is prime and its reverse (1887199) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9917881 - 2⁵ = 9917849 is a prime.

It is a super-2 number, since 2×9917881² = 196728727060322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (9917891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4958940 + 4958941.

It is an arithmetic number, because the mean of its divisors is an integer number (4958941).

Almost surely, 2^9917881 is an apocalyptic number.

It is an amenable number.

9917881 is a deficient number, since it is larger than the sum of its proper divisors (1).

9917881 is an equidigital number, since it uses as much as digits as its factorization.

9917881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36288, while the sum is 43.

The square root of 9917881 is about 3149.2667400524. The cubic root of 9917881 is about 214.8521139131.

The spelling of 9917881 in words is "nine million, nine hundred seventeen thousand, eight hundred eighty-one".