6666611509 has 4 divisors (see below), whose sum is σ = 6671284704. Its totient is φ = 6661938316.

The previous prime is 6666611503. The next prime is 6666611531. The reversal of 6666611509 is 9051166666.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 6666611509 - 2⁵ = 6666611477 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 (6666611503) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2334457 + ... + 2337310.

It is an arithmetic number, because the mean of its divisors is an integer number (1667821176).

Almost surely, 2^6666611509 is an apocalyptic number.

It is an amenable number.

6666611509 is a deficient number, since it is larger than the sum of its proper divisors (4673195).

6666611509 is a wasteful number, since it uses less digits than its factorization.

6666611509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4673194.

The product of its (nonzero) digits is 349920, while the sum is 46.

The square root of 6666611509 is about 81649.3203217271. The cubic root of 6666611509 is about 1882.0668672126.

The spelling of 6666611509 in words is "six billion, six hundred sixty-six million, six hundred eleven thousand, five hundred nine".