9139981 has 2 divisors, whose sum is σ = 9139982. Its totient is φ = 9139980.

The previous prime is 9139973. The next prime is 9139987. The reversal of 9139981 is 1899319.

9139981 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6916900 + 2223081 = 2630^2 + 1491^2 .

It is a cyclic number.

It is not a de Polignac number, because 9139981 - 2³ = 9139973 is a prime.

It is a super-2 number, since 2×9139981² = 167078505360722, which contains 22 as substring.

It is a Chen prime.

9139981 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9139987) 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, 4569990 + 4569991.

It is an arithmetic number, because the mean of its divisors is an integer number (4569991).

Almost surely, 2^9139981 is an apocalyptic number.

It is an amenable number.

9139981 is a deficient number, since it is larger than the sum of its proper divisors (1).

9139981 is an equidigital number, since it uses as much as digits as its factorization.

9139981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17496, while the sum is 40.

The square root of 9139981 is about 3023.2401492439. The cubic root of 9139981 is about 209.0812547012.

The spelling of 9139981 in words is "nine million, one hundred thirty-nine thousand, nine hundred eighty-one".