221939890 has 8 divisors (see below), whose sum is σ = 399491820. Its totient is φ = 88775952.

The previous prime is 221939873. The next prime is 221939909. The reversal of 221939890 is 98939122.

It can be written as a sum of positive squares in 2 ways, for example, as 215473041 + 6466849 = 14679^2 + 2543^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 11096985 + ... + 11097004.

Almost surely, 2^221939890 is an apocalyptic number.

221939890 is a deficient number, since it is larger than the sum of its proper divisors (177551930).

221939890 is a wasteful number, since it uses less digits than its factorization.

221939890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22193996.

The product of its (nonzero) digits is 69984, while the sum is 43.

The square root of 221939890 is about 14897.6471296645. The cubic root of 221939890 is about 605.4502397191.

The spelling of 221939890 in words is "two hundred twenty-one million, nine hundred thirty-nine thousand, eight hundred ninety".