18331459649 has 4 divisors (see below), whose sum is σ = 18332799060. Its totient is φ = 18330120240.

The previous prime is 18331459637. The next prime is 18331459697. The reversal of 18331459649 is 94695413381.

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 5805373249 + 12526086400 = 76193^2 + 111920^2 .

It is a cyclic number.

It is not a de Polignac number, because 18331459649 - 2²⁸ = 18063024193 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 18331459649.

It is not an unprimeable number, because it can be changed into a prime (18331459049) 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, 648962 + ... + 676619.

It is an arithmetic number, because the mean of its divisors is an integer number (4583199765).

Almost surely, 2^18331459649 is an apocalyptic number.

It is an amenable number.

18331459649 is a deficient number, since it is larger than the sum of its proper divisors (1339411).

18331459649 is a wasteful number, since it uses less digits than its factorization.

18331459649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1339410.

The product of its digits is 2799360, while the sum is 53.

The spelling of 18331459649 in words is "eighteen billion, three hundred thirty-one million, four hundred fifty-nine thousand, six hundred forty-nine".