666644787446665 has 8 divisors (see below), whose sum is σ = 800465431328640. Its totient is φ = 532988039028912.

The previous prime is 666644787446663. The next prime is 666644787446719. The reversal of 666644787446665 is 566644787446666.

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 666644787446665 - 2¹ = 666644787446663 is a prime.

It is not an unprimeable number, because it can be changed into a prime (666644787446663) 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, 40973857105 + ... + 40973873374.

It is an arithmetic number, because the mean of its divisors is an integer number (100058178916080).

Almost surely, 2^{666644787446665} is an apocalyptic number.

It is an amenable number.

666644787446665 is a deficient number, since it is larger than the sum of its proper divisors (133820643881975).

666644787446665 is a wasteful number, since it uses less digits than its factorization.

666644787446665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81947732111.

The product of its digits is 140460687360, while the sum is 85.

Subtracting from 666644787446665 its reverse (566644787446666), we obtain a palindrome (99999999999999).

The spelling of 666644787446665 in words is "six hundred sixty-six trillion, six hundred forty-four billion, seven hundred eighty-seven million, four hundred forty-six thousand, six hundred sixty-five".