666658511 has 4 divisors (see below), whose sum is σ = 667995000. Its totient is φ = 665322024.

The previous prime is 666658469. The next prime is 666658543. The reversal of 666658511 is 115856666.

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

It is a cyclic number.

It is not a de Polignac number, because 666658511 - 2²⁶ = 599549647 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 (666658561) 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 3 ways as a sum of consecutive naturals, for example, 667496 + ... + 668493.

It is an arithmetic number, because the mean of its divisors is an integer number (166998750).

Almost surely, 2^666658511 is an apocalyptic number.

666658511 is a deficient number, since it is larger than the sum of its proper divisors (1336489).

666658511 is a wasteful number, since it uses less digits than its factorization.

666658511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1336488.

The product of its digits is 259200, while the sum is 44.

The square root of 666658511 is about 25819.7310404272. The cubic root of 666658511 is about 873.5769024062.

The spelling of 666658511 in words is "six hundred sixty-six million, six hundred fifty-eight thousand, five hundred eleven".