66623444432665 has 16 divisors (see below), whose sum is σ = 80267707994112. Its totient is φ = 53085749653504.

The previous prime is 66623444432651. The next prime is 66623444432723. The reversal of 66623444432665 is 56623444432666.

It is a cyclic number.

It is not a de Polignac number, because 66623444432665 - 2⁷ = 66623444432537 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9426792 + ... + 14903398.

It is an arithmetic number, because the mean of its divisors is an integer number (5016731749632).

Almost surely, 2^{66623444432665} is an apocalyptic number.

It is an amenable number.

66623444432665 is a deficient number, since it is larger than the sum of its proper divisors (13644263561447).

66623444432665 is a wasteful number, since it uses less digits than its factorization.

66623444432665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5486336.

The product of its digits is 358318080, while the sum is 61.

Subtracting from 66623444432665 its reverse (56623444432666), we obtain a palindrome (9999999999999).

The spelling of 66623444432665 in words is "sixty-six trillion, six hundred twenty-three billion, four hundred forty-four million, four hundred thirty-two thousand, six hundred sixty-five".