18449881919 has 4 divisors (see below), whose sum is σ = 21085579344. Its totient is φ = 15814184496.

The previous prime is 18449881897. The next prime is 18449881949. The reversal of 18449881919 is 91918894481.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18449881919 is a prime.

It is a super-2 number, since 2×18449881919² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18449881949) 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, 1317848702 + ... + 1317848715.

It is an arithmetic number, because the mean of its divisors is an integer number (5271394836).

Almost surely, 2^18449881919 is an apocalyptic number.

18449881919 is a deficient number, since it is larger than the sum of its proper divisors (2635697425).

18449881919 is an equidigital number, since it uses as much as digits as its factorization.

18449881919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2635697424.

The product of its digits is 5971968, while the sum is 62.

The spelling of 18449881919 in words is "eighteen billion, four hundred forty-nine million, eight hundred eighty-one thousand, nine hundred nineteen".