666500101 has 4 divisors (see below), whose sum is σ = 670182604. Its totient is φ = 662817600.

The previous prime is 666500099. The next prime is 666500119. The reversal of 666500101 is 101005666.

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 35988001 + 630512100 = 5999^2 + 25110^2 .

It is a cyclic number.

It is not a de Polignac number, because 666500101 - 2¹ = 666500099 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 (666500161) 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, 1840980 + ... + 1841341.

It is an arithmetic number, because the mean of its divisors is an integer number (167545651).

Almost surely, 2^666500101 is an apocalyptic number.

It is an amenable number.

666500101 is a deficient number, since it is larger than the sum of its proper divisors (3682503).

666500101 is a wasteful number, since it uses less digits than its factorization.

666500101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3682502.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 666500101 is about 25816.6632429522. The cubic root of 666500101 is about 873.5077044200.

Adding to 666500101 its reverse (101005666), we get a palindrome (767505767).

The spelling of 666500101 in words is "six hundred sixty-six million, five hundred thousand, one hundred one".