201221906 has 8 divisors (see below), whose sum is σ = 301895040. Its totient is φ = 100590228.

The previous prime is 201221893. The next prime is 201221921. The reversal of 201221906 is 609122102.

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

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9035 + ... + 22001.

It is an arithmetic number, because the mean of its divisors is an integer number (37736880).

Almost surely, 2^201221906 is an apocalyptic number.

201221906 is a deficient number, since it is larger than the sum of its proper divisors (100673134).

201221906 is a wasteful number, since it uses less digits than its factorization.

201221906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20728.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 201221906 is about 14185.2707411596. The cubic root of 201221906 is about 585.9920887158.

The spelling of 201221906 in words is "two hundred one million, two hundred twenty-one thousand, nine hundred six".