221999999 has 4 divisors (see below), whose sum is σ = 239076936. Its totient is φ = 204923064.

The previous prime is 221999993. The next prime is 222000019. The reversal of 221999999 is 999999122.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 221999999 - 2⁴ = 221999983 is a prime.

It is a Duffinian number.

221999999 is a modest number, since divided by 99999 gives 2219 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221999993) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8538449 + ... + 8538474.

It is an arithmetic number, because the mean of its divisors is an integer number (59769234).

Almost surely, 2^221999999 is an apocalyptic number.

221999999 is a deficient number, since it is larger than the sum of its proper divisors (17076937).

221999999 is a wasteful number, since it uses less digits than its factorization.

221999999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17076936.

The product of its digits is 2125764, while the sum is 59.

The square root of 221999999 is about 14899.6643921935. The cubic root of 221999999 is about 605.5048937419.

The spelling of 221999999 in words is "two hundred twenty-one million, nine hundred ninety-nine thousand, nine hundred ninety-nine".