9971861 has 2 divisors, whose sum is σ = 9971862. Its totient is φ = 9971860.

The previous prime is 9971839. The next prime is 9971881. The reversal of 9971861 is 1681799.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7102225 + 2869636 = 2665^2 + 1694^2 .

It is a cyclic number.

It is not a de Polignac number, because 9971861 - 2²² = 5777557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9971881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4985930 + 4985931.

It is an arithmetic number, because the mean of its divisors is an integer number (4985931).

Almost surely, 2^9971861 is an apocalyptic number.

It is an amenable number.

9971861 is a deficient number, since it is larger than the sum of its proper divisors (1).

9971861 is an equidigital number, since it uses as much as digits as its factorization.

9971861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27216, while the sum is 41.

The square root of 9971861 is about 3157.8253593256. The cubic root of 9971861 is about 215.2412003707.

The spelling of 9971861 in words is "nine million, nine hundred seventy-one thousand, eight hundred sixty-one".