999906121 has 2 divisors, whose sum is σ = 999906122. Its totient is φ = 999906120.

The previous prime is 999906113. The next prime is 999906169. The reversal of 999906121 is 121609999.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 938503225 + 61402896 = 30635^2 + 7836^2 .

It is a cyclic number.

It is not a de Polignac number, because 999906121 - 2³ = 999906113 is a prime.

It is not a weakly prime, because it can be changed into another prime (999906421) 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, 499953060 + 499953061.

It is an arithmetic number, because the mean of its divisors is an integer number (499953061).

Almost surely, 2^999906121 is an apocalyptic number.

It is an amenable number.

999906121 is a deficient number, since it is larger than the sum of its proper divisors (1).

999906121 is an equidigital number, since it uses as much as digits as its factorization.

999906121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 78732, while the sum is 46.

The square root of 999906121 is about 31621.2922095224. The cubic root of 999906121 is about 999.9687060207.

The spelling of 999906121 in words is "nine hundred ninety-nine million, nine hundred six thousand, one hundred twenty-one".