9920648821 has 2 divisors, whose sum is σ = 9920648822. Its totient is φ = 9920648820.

The previous prime is 9920648797. The next prime is 9920648833. The reversal of 9920648821 is 1288460299.

9920648821 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 can be written as a sum of positive squares in only one way, i.e., 5823368721 + 4097280100 = 76311^2 + 64010^2 .

It is a cyclic number.

It is not a de Polignac number, because 9920648821 - 2¹³ = 9920640629 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9920648851) 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, 4960324410 + 4960324411.

It is an arithmetic number, because the mean of its divisors is an integer number (4960324411).

Almost surely, 2^9920648821 is an apocalyptic number.

It is an amenable number.

9920648821 is a deficient number, since it is larger than the sum of its proper divisors (1).

9920648821 is an equidigital number, since it uses as much as digits as its factorization.

9920648821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 497664, while the sum is 49.

The square root of 9920648821 is about 99602.4538904539. The cubic root of 9920648821 is about 2148.7209858796.

The spelling of 9920648821 in words is "nine billion, nine hundred twenty million, six hundred forty-eight thousand, eight hundred twenty-one".