999939121 has 2 divisors, whose sum is σ = 999939122. Its totient is φ = 999939120.

The previous prime is 999939091. The next prime is 999939137. The reversal of 999939121 is 121939999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 842160400 + 157778721 = 29020^2 + 12561^2 .

It is an emirp because it is prime and its reverse (121939999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 999939121 - 2⁵ = 999939089 is a prime.

It is not a weakly prime, because it can be changed into another prime (999939821) 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, 499969560 + 499969561.

It is an arithmetic number, because the mean of its divisors is an integer number (499969561).

Almost surely, 2^999939121 is an apocalyptic number.

It is an amenable number.

999939121 is a deficient number, since it is larger than the sum of its proper divisors (1).

999939121 is an equidigital number, since it uses as much as digits as its factorization.

999939121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 354294, while the sum is 52.

The square root of 999939121 is about 31621.8140055247. The cubic root of 999939121 is about 999.9797065882.

The spelling of 999939121 in words is "nine hundred ninety-nine million, nine hundred thirty-nine thousand, one hundred twenty-one".