9991000087 has 2 divisors, whose sum is σ = 9991000088. Its totient is φ = 9991000086.

The previous prime is 9991000049. The next prime is 9991000099. The reversal of 9991000087 is 7800001999.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 9991000087 - 2¹⁵ = 9990967319 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9991000027) 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, 4995500043 + 4995500044.

It is an arithmetic number, because the mean of its divisors is an integer number (4995500044).

Almost surely, 2^9991000087 is an apocalyptic number.

9991000087 is a deficient number, since it is larger than the sum of its proper divisors (1).

9991000087 is an equidigital number, since it uses as much as digits as its factorization.

9991000087 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40824, while the sum is 43.

The square root of 9991000087 is about 99954.9903056371. The cubic root of 9991000087 is about 2153.7881718804.

The spelling of 9991000087 in words is "nine billion, nine hundred ninety-one million, eighty-seven", and thus it is an aban number.