6665165561551 has 8 divisors (see below), whose sum is σ = 7617681391520. Its totient is φ = 5712737061888.

The previous prime is 6665165561491. The next prime is 6665165561573. The reversal of 6665165561551 is 1551655615666.

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

It is a cyclic number.

It is not a de Polignac number, because 6665165561551 - 2¹⁷ = 6665165430479 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 (6665165561581) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21668946 + ... + 21974383.

It is an arithmetic number, because the mean of its divisors is an integer number (952210173940).

Almost surely, 2^{6665165561551} is an apocalyptic number.

6665165561551 is a deficient number, since it is larger than the sum of its proper divisors (952515829969).

6665165561551 is a wasteful number, since it uses less digits than its factorization.

6665165561551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43665153.

The product of its digits is 24300000, while the sum is 58.

The spelling of 6665165561551 in words is "six trillion, six hundred sixty-five billion, one hundred sixty-five million, five hundred sixty-one thousand, five hundred fifty-one".