221939805 has 16 divisors (see below), whose sum is σ = 358364160. Its totient is φ = 117281088.

The previous prime is 221939789. The next prime is 221939843. The reversal of 221939805 is 508939122.

221939805 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 221939805 - 2⁴ = 221939789 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 66237 + ... + 69506.

It is an arithmetic number, because the mean of its divisors is an integer number (22397760).

Almost surely, 2^221939805 is an apocalyptic number.

It is an amenable number.

221939805 is a deficient number, since it is larger than the sum of its proper divisors (136424355).

221939805 is a wasteful number, since it uses less digits than its factorization.

221939805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135860.

The product of its (nonzero) digits is 38880, while the sum is 39.

The square root of 221939805 is about 14897.6442768647. The cubic root of 221939805 is about 605.4501624260.

It can be divided in two parts, 2219 and 39805, that added together give a palindrome (42024).

The spelling of 221939805 in words is "two hundred twenty-one million, nine hundred thirty-nine thousand, eight hundred five".