666504109 has 4 divisors (see below), whose sum is σ = 668482204. Its totient is φ = 664526016.

The previous prime is 666504107. The next prime is 666504127. The reversal of 666504109 is 901405666.

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 256320100 + 410184009 = 16010^2 + 20253^2 .

It is a cyclic number.

It is not a de Polignac number, because 666504109 - 2¹ = 666504107 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, 988542 + ... + 989215.

It is an arithmetic number, because the mean of its divisors is an integer number (167120551).

Almost surely, 2^666504109 is an apocalyptic number.

It is an amenable number.

666504109 is a deficient number, since it is larger than the sum of its proper divisors (1978095).

666504109 is a wasteful number, since it uses less digits than its factorization.

666504109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1978094.

The product of its (nonzero) digits is 38880, while the sum is 37.

The square root of 666504109 is about 25816.7408671195. The cubic root of 666504109 is about 873.5094553634.

The spelling of 666504109 in words is "six hundred sixty-six million, five hundred four thousand, one hundred nine".