996808721 has 2 divisors, whose sum is σ = 996808722. Its totient is φ = 996808720.

The previous prime is 996808699. The next prime is 996808801. The reversal of 996808721 is 127808699.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 885717121 + 111091600 = 29761^2 + 10540^2 .

It is a cyclic number.

It is not a de Polignac number, because 996808721 - 2²⁶ = 929699857 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 996808721.

It is not a weakly prime, because it can be changed into another prime (996802721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 498404360 + 498404361.

It is an arithmetic number, because the mean of its divisors is an integer number (498404361).

Almost surely, 2^996808721 is an apocalyptic number.

It is an amenable number.

996808721 is a deficient number, since it is larger than the sum of its proper divisors (1).

996808721 is an equidigital number, since it uses as much as digits as its factorization.

996808721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 435456, while the sum is 50.

The square root of 996808721 is about 31572.2777290458. The cubic root of 996808721 is about 998.9351067382.

The spelling of 996808721 in words is "nine hundred ninety-six million, eight hundred eight thousand, seven hundred twenty-one".