312221999 has 2 divisors, whose sum is σ = 312222000. Its totient is φ = 312221998.

The previous prime is 312221989. The next prime is 312222019. The reversal of 312221999 is 999122213.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 312221999 - 2²⁴ = 295444783 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (312221909) 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, 156110999 + 156111000.

It is an arithmetic number, because the mean of its divisors is an integer number (156111000).

Almost surely, 2^312221999 is an apocalyptic number.

312221999 is a deficient number, since it is larger than the sum of its proper divisors (1).

312221999 is an equidigital number, since it uses as much as digits as its factorization.

312221999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17496, while the sum is 38.

The square root of 312221999 is about 17669.8047244445. The cubic root of 312221999 is about 678.4031148979.

The spelling of 312221999 in words is "three hundred twelve million, two hundred twenty-one thousand, nine hundred ninety-nine".