18218744649 has 48 divisors (see below), whose sum is σ = 30331536768. Its totient is φ = 10322436096.

The previous prime is 18218744633. The next prime is 18218744653. The reversal of 18218744649 is 94644781281.

18218744649 is a `hidden beast` number, since 1 + 82 + 1 + 87 + 446 + 49 = 666.

It is not a de Polignac number, because 18218744649 - 2⁴ = 18218744633 is a prime.

It is a super-2 number, since 2×18218744649² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 18218744595 and 18218744604.

It is not an unprimeable number, because it can be changed into a prime (18218744669) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3672879 + ... + 3677835.

It is an arithmetic number, because the mean of its divisors is an integer number (631907016).

Almost surely, 2^18218744649 is an apocalyptic number.

It is an amenable number.

18218744649 is a deficient number, since it is larger than the sum of its proper divisors (12112792119).

18218744649 is a wasteful number, since it uses less digits than its factorization.

18218744649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5454 (or 5451 counting only the distinct ones).

The product of its digits is 3096576, while the sum is 54.

The spelling of 18218744649 in words is "eighteen billion, two hundred eighteen million, seven hundred forty-four thousand, six hundred forty-nine".