66344043621 has 16 divisors (see below), whose sum is σ = 88779487104. Its totient is φ = 44069270784.

The previous prime is 66344043607. The next prime is 66344043643. The reversal of 66344043621 is 12634044366.

It is not a de Polignac number, because 66344043621 - 2¹⁴ = 66344027237 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 66344043621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66344044621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 895425 + ... + 966681.

It is an arithmetic number, because the mean of its divisors is an integer number (5548717944).

Almost surely, 2^66344043621 is an apocalyptic number.

It is an amenable number.

66344043621 is a deficient number, since it is larger than the sum of its proper divisors (22435443483).

66344043621 is a wasteful number, since it uses less digits than its factorization.

66344043621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72380.

The product of its (nonzero) digits is 248832, while the sum is 39.

Adding to 66344043621 its reverse (12634044366), we get a palindrome (78978087987).

The spelling of 66344043621 in words is "sixty-six billion, three hundred forty-four million, forty-three thousand, six hundred twenty-one".