999992221 has 2 divisors, whose sum is σ = 999992222. Its totient is φ = 999992220.

The previous prime is 999992209. The next prime is 999992263. The reversal of 999992221 is 122299999.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 938196900 + 61795321 = 30630^2 + 7861^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-999992221 is a prime.

It is a nialpdrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999992281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499996110 + 499996111.

It is an arithmetic number, because the mean of its divisors is an integer number (499996111).

Almost surely, 2^999992221 is an apocalyptic number.

It is an amenable number.

999992221 is a deficient number, since it is larger than the sum of its proper divisors (1).

999992221 is an equidigital number, since it uses as much as digits as its factorization.

999992221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 472392, while the sum is 52.

The square root of 999992221 is about 31622.6536046550. The cubic root of 999992221 is about 999.9974069933.

The spelling of 999992221 in words is "nine hundred ninety-nine million, nine hundred ninety-two thousand, two hundred twenty-one".