221840806 has 16 divisors (see below), whose sum is σ = 365875200. Its totient is φ = 100041480.

The previous prime is 221840797. The next prime is 221840813. The reversal of 221840806 is 608048122.

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 36906 + ... + 42493.

It is an arithmetic number, because the mean of its divisors is an integer number (22867200).

Almost surely, 2^221840806 is an apocalyptic number.

221840806 is a deficient number, since it is larger than the sum of its proper divisors (144034394).

221840806 is a wasteful number, since it uses less digits than its factorization.

221840806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79539.

The product of its (nonzero) digits is 6144, while the sum is 31.

The square root of 221840806 is about 14894.3212668453. The cubic root of 221840806 is about 605.3601261884.

Adding to 221840806 its reverse (608048122), we get a palindrome (829888928).

The spelling of 221840806 in words is "two hundred twenty-one million, eight hundred forty thousand, eight hundred six".