9991254991 has 2 divisors, whose sum is σ = 9991254992. Its totient is φ = 9991254990.

The previous prime is 9991254983. The next prime is 9991255037. The reversal of 9991254991 is 1994521999.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 9991254991 - 2³ = 9991254983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9991254941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4995627495 + 4995627496.

It is an arithmetic number, because the mean of its divisors is an integer number (4995627496).

Almost surely, 2^9991254991 is an apocalyptic number.

9991254991 is a deficient number, since it is larger than the sum of its proper divisors (1).

9991254991 is an equidigital number, since it uses as much as digits as its factorization.

9991254991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2361960, while the sum is 58.

The square root of 9991254991 is about 99956.2653914201. The cubic root of 9991254991 is about 2153.8064885169.

The spelling of 9991254991 in words is "nine billion, nine hundred ninety-one million, two hundred fifty-four thousand, nine hundred ninety-one".