201666921 has 8 divisors (see below), whose sum is σ = 280580160. Its totient is φ = 128599152.

The previous prime is 201666911. The next prime is 201666923. The reversal of 201666921 is 129666102.

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

It is not a de Polignac number, because 201666921 - 2⁵ = 201666889 is a prime.

It is not an unprimeable number, because it can be changed into a prime (201666923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1461286 + ... + 1461423.

It is an arithmetic number, because the mean of its divisors is an integer number (35072520).

Almost surely, 2^201666921 is an apocalyptic number.

It is an amenable number.

201666921 is a deficient number, since it is larger than the sum of its proper divisors (78913239).

201666921 is a wasteful number, since it uses less digits than its factorization.

201666921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2922735.

The product of its (nonzero) digits is 7776, while the sum is 33.

The square root of 201666921 is about 14200.9478908980. The cubic root of 201666921 is about 586.4237568677.

The spelling of 201666921 in words is "two hundred one million, six hundred sixty-six thousand, nine hundred twenty-one".