18385461649 has 3 divisors (see below), whose sum is σ = 18385597243. Its totient is φ = 18385326056.

The previous prime is 18385461641. The next prime is 18385461683. The reversal of 18385461649 is 94616458381.

The square root of 18385461649 is 135593.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 18293915025 + 91546624 = 135255^2 + 9568^2 .

It is not a de Polignac number, because 18385461649 - 2³ = 18385461641 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18385461649.

It is not an unprimeable number, because it can be changed into a prime (18385461641) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 67797 + ... + 203389.

Almost surely, 2^18385461649 is an apocalyptic number.

18385461649 is the 135593-rd square number.

18385461649 is the 67797-th centered octagonal number.

It is an amenable number.

18385461649 is a deficient number, since it is larger than the sum of its proper divisors (135594).

18385461649 is an frugal number, since it uses more digits than its factorization.

18385461649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 271186 (or 135593 counting only the distinct ones).

The product of its digits is 4976640, while the sum is 55.

The spelling of 18385461649 in words is "eighteen billion, three hundred eighty-five million, four hundred sixty-one thousand, six hundred forty-nine".