9920571779 has 2 divisors, whose sum is σ = 9920571780. Its totient is φ = 9920571778.

The previous prime is 9920571719. The next prime is 9920571841. The reversal of 9920571779 is 9771750299.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9920571779 is a prime.

It is not a weakly prime, because it can be changed into another prime (9920571719) 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, 4960285889 + 4960285890.

It is an arithmetic number, because the mean of its divisors is an integer number (4960285890).

Almost surely, 2^9920571779 is an apocalyptic number.

9920571779 is a deficient number, since it is larger than the sum of its proper divisors (1).

9920571779 is an equidigital number, since it uses as much as digits as its factorization.

9920571779 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2500470, while the sum is 56.

The square root of 9920571779 is about 99602.0671422034. The cubic root of 9920571779 is about 2148.7154236698.

The spelling of 9920571779 in words is "nine billion, nine hundred twenty million, five hundred seventy-one thousand, seven hundred seventy-nine".