9931861 has 2 divisors, whose sum is σ = 9931862. Its totient is φ = 9931860.

The previous prime is 9931853. The next prime is 9931897. The reversal of 9931861 is 1681399.

9931861 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9579025 + 352836 = 3095^2 + 594^2 .

It is a cyclic number.

It is not a de Polignac number, because 9931861 - 2³ = 9931853 is a prime.

9931861 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 9931861.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9931841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4965930 + 4965931.

It is an arithmetic number, because the mean of its divisors is an integer number (4965931).

Almost surely, 2^9931861 is an apocalyptic number.

It is an amenable number.

9931861 is a deficient number, since it is larger than the sum of its proper divisors (1).

9931861 is an equidigital number, since it uses as much as digits as its factorization.

9931861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11664, while the sum is 37.

The square root of 9931861 is about 3151.4855227337. The cubic root of 9931861 is about 214.9530165949.

The spelling of 9931861 in words is "nine million, nine hundred thirty-one thousand, eight hundred sixty-one".