221999 has 2 divisors, whose sum is σ = 222000. Its totient is φ = 221998.

The previous prime is 221989. The next prime is 222007. The reversal of 221999 is 999122.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221999 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

221999 is a modest number, since divided by 999 gives 221 as remainder.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 221999.

It is not a weakly prime, because it can be changed into another prime (221909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110999 + 111000.

It is an arithmetic number, because the mean of its divisors is an integer number (111000).

2²²¹⁹⁹⁹ is an apocalyptic number.

221999 is a deficient number, since it is larger than the sum of its proper divisors (1).

221999 is an equidigital number, since it uses as much as digits as its factorization.

221999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2916, while the sum is 32.

The square root of 221999 is about 471.1676983835. The cubic root of 221999 is about 60.5503985483.

The spelling of 221999 in words is "two hundred twenty-one thousand, nine hundred ninety-nine".