18664307547649 has 4 divisors (see below), whose sum is σ = 18664357729860. Its totient is φ = 18664257365440.

The previous prime is 18664307547631. The next prime is 18664307547701. The reversal of 18664307547649 is 94674570346681.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9470483082225 + 9193824465424 = 3077415^2 + 3032132^2 .

It is a cyclic number.

It is not a de Polignac number, because 18664307547649 - 2¹¹ = 18664307545601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18664307547349) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24529012 + ... + 25278469.

It is an arithmetic number, because the mean of its divisors is an integer number (4666089432465).

Almost surely, 2^{18664307547649} is an apocalyptic number.

It is an amenable number.

18664307547649 is a deficient number, since it is larger than the sum of its proper divisors (50182211).

18664307547649 is an equidigital number, since it uses as much as digits as its factorization.

18664307547649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50182210.

The product of its (nonzero) digits is 731566080, while the sum is 70.

The spelling of 18664307547649 in words is "eighteen trillion, six hundred sixty-four billion, three hundred seven million, five hundred forty-seven thousand, six hundred forty-nine".