201666501 has 12 divisors (see below), whose sum is σ = 300693120. Its totient is φ = 130107240.

The previous prime is 201666499. The next prime is 201666533. The reversal of 201666501 is 105666102.

It is a happy number.

It is not a de Polignac number, because 201666501 - 2¹ = 201666499 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201666541) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 361131 + ... + 361688.

It is an arithmetic number, because the mean of its divisors is an integer number (25057760).

Almost surely, 2^201666501 is an apocalyptic number.

It is an amenable number.

201666501 is a deficient number, since it is larger than the sum of its proper divisors (99026619).

201666501 is a wasteful number, since it uses less digits than its factorization.

201666501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 722856 (or 722853 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 201666501 is about 14200.9331031450. The cubic root of 201666501 is about 586.4233497639.

The spelling of 201666501 in words is "two hundred one million, six hundred sixty-six thousand, five hundred one".