9712779991 has 2 divisors, whose sum is σ = 9712779992. Its totient is φ = 9712779990.

The previous prime is 9712779977. The next prime is 9712780003. The reversal of 9712779991 is 1999772179.

9712779991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is an emirp because it is prime and its reverse (1999772179) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9712779991 - 2⁷ = 9712779863 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9712779691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4856389995 + 4856389996.

It is an arithmetic number, because the mean of its divisors is an integer number (4856389996).

Almost surely, 2^9712779991 is an apocalyptic number.

9712779991 is a deficient number, since it is larger than the sum of its proper divisors (1).

9712779991 is an equidigital number, since it uses as much as digits as its factorization.

9712779991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4500846, while the sum is 61.

The square root of 9712779991 is about 98553.4372358468. The cubic root of 9712779991 is about 2133.6074402484.

The spelling of 9712779991 in words is "nine billion, seven hundred twelve million, seven hundred seventy-nine thousand, nine hundred ninety-one".