666531611 has 8 divisors (see below), whose sum is σ = 685048320. Its totient is φ = 648267048.

The previous prime is 666531557. The next prime is 666531707. The reversal of 666531611 is 116135666.

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

It is not a de Polignac number, because 666531611 - 2²² = 662337307 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666531011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 57671 + ... + 68256.

It is an arithmetic number, because the mean of its divisors is an integer number (85631040).

Almost surely, 2^666531611 is an apocalyptic number.

666531611 is a deficient number, since it is larger than the sum of its proper divisors (18516709).

666531611 is a wasteful number, since it uses less digits than its factorization.

666531611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126073.

The product of its digits is 19440, while the sum is 35.

The square root of 666531611 is about 25817.2735005074. The cubic root of 666531611 is about 873.5214697563.

The spelling of 666531611 in words is "six hundred sixty-six million, five hundred thirty-one thousand, six hundred eleven".