9991801679 has 2 divisors, whose sum is σ = 9991801680. Its totient is φ = 9991801678.

The previous prime is 9991801669. The next prime is 9991801709. The reversal of 9991801679 is 9761081999.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 9991801679 - 2⁸ = 9991801423 is a prime.

It is a super-2 number, since 2×9991801679² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9991801609) 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, 4995900839 + 4995900840.

It is an arithmetic number, because the mean of its divisors is an integer number (4995900840).

Almost surely, 2^9991801679 is an apocalyptic number.

9991801679 is a deficient number, since it is larger than the sum of its proper divisors (1).

9991801679 is an equidigital number, since it uses as much as digits as its factorization.

9991801679 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2204496, while the sum is 59.

The square root of 9991801679 is about 99958.9999899959. Note that the first 4 decimals coincide. The cubic root of 9991801679 is about 2153.8457708255.

The spelling of 9991801679 in words is "nine billion, nine hundred ninety-one million, eight hundred one thousand, six hundred seventy-nine".