999319021 has 2 divisors, whose sum is σ = 999319022. Its totient is φ = 999319020.

The previous prime is 999319001. The next prime is 999319031. The reversal of 999319021 is 120913999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 882981225 + 116337796 = 29715^2 + 10786^2 .

It is an emirp because it is prime and its reverse (120913999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 999319021 - 2⁷ = 999318893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999319001) 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, 499659510 + 499659511.

It is an arithmetic number, because the mean of its divisors is an integer number (499659511).

Almost surely, 2^999319021 is an apocalyptic number.

It is an amenable number.

999319021 is a deficient number, since it is larger than the sum of its proper divisors (1).

999319021 is an equidigital number, since it uses as much as digits as its factorization.

999319021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 39366, while the sum is 43.

The square root of 999319021 is about 31612.0075446024. The cubic root of 999319021 is about 999.7729554547.

The spelling of 999319021 in words is "nine hundred ninety-nine million, three hundred nineteen thousand, twenty-one".