666506101 has 4 divisors (see below), whose sum is σ = 689489100. Its totient is φ = 643523104.

The previous prime is 666506041. The next prime is 666506189. The reversal of 666506101 is 101605666.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 548262225 + 118243876 = 23415^2 + 10874^2 .

It is a cyclic number.

It is not a de Polignac number, because 666506101 - 2⁹ = 666505589 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666504101) by changing a digit.

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, 11491456 + ... + 11491513.

It is an arithmetic number, because the mean of its divisors is an integer number (172372275).

Almost surely, 2^666506101 is an apocalyptic number.

It is an amenable number.

666506101 is a deficient number, since it is larger than the sum of its proper divisors (22982999).

666506101 is a wasteful number, since it uses less digits than its factorization.

666506101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22982998.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 666506101 is about 25816.7794467087. The cubic root of 666506101 is about 873.5103255902.

The spelling of 666506101 in words is "six hundred sixty-six million, five hundred six thousand, one hundred one".