6666155561009 has 64 divisors (see below), whose sum is σ = 7957647360000. Its totient is φ = 5580680434560.

The previous prime is 6666155560993. The next prime is 6666155561029. The reversal of 6666155561009 is 9001655516666.

It is a happy number.

It is not a de Polignac number, because 6666155561009 - 2⁴ = 6666155560993 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (6666155561029) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1355182652 + ... + 1355187570.

It is an arithmetic number, because the mean of its divisors is an integer number (124338240000).

Almost surely, 2^{6666155561009} is an apocalyptic number.

It is an amenable number.

6666155561009 is a deficient number, since it is larger than the sum of its proper divisors (1291491798991).

6666155561009 is a wasteful number, since it uses less digits than its factorization.

6666155561009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5563 (or 5549 counting only the distinct ones).

The product of its (nonzero) digits is 8748000, while the sum is 56.

The spelling of 6666155561009 in words is "six trillion, six hundred sixty-six billion, one hundred fifty-five million, five hundred sixty-one thousand, nine".