9959981 has 2 divisors, whose sum is σ = 9959982. Its totient is φ = 9959980.

The previous prime is 9959947. The next prime is 9959987. The reversal of 9959981 is 1899599.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8094025 + 1865956 = 2845^2 + 1366^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9959981 is a prime.

It is a super-2 number, since 2×9959981² = 198402443040722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9959987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4979990 + 4979991.

It is an arithmetic number, because the mean of its divisors is an integer number (4979991).

Almost surely, 2^9959981 is an apocalyptic number.

It is an amenable number.

9959981 is a deficient number, since it is larger than the sum of its proper divisors (1).

9959981 is an equidigital number, since it uses as much as digits as its factorization.

9959981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 262440, while the sum is 50.

The square root of 9959981 is about 3155.9437574203. The cubic root of 9959981 is about 215.1556903678.

The spelling of 9959981 in words is "nine million, nine hundred fifty-nine thousand, nine hundred eighty-one".