18551337449 has 4 divisors (see below), whose sum is σ = 18552199236. Its totient is φ = 18550475664.

The previous prime is 18551337443. The next prime is 18551337481. The reversal of 18551337449 is 94473315581.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 94473315581 = 107 ⋅882928183.

It can be written as a sum of positive squares in 2 ways, for example, as 12356545600 + 6194791849 = 111160^2 + 78707^2 .

It is a cyclic number.

It is not a de Polignac number, because 18551337449 - 2⁴ = 18551337433 is a prime.

It is a super-2 number, since 2×18551337449² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 18551337397 and 18551337406.

It is not an unprimeable number, because it can be changed into a prime (18551337443) 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, 397754 + ... + 441939.

It is an arithmetic number, because the mean of its divisors is an integer number (4638049809).

Almost surely, 2^18551337449 is an apocalyptic number.

It is an amenable number.

18551337449 is a deficient number, since it is larger than the sum of its proper divisors (861787).

18551337449 is an equidigital number, since it uses as much as digits as its factorization.

18551337449 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 861786.

The product of its digits is 1814400, while the sum is 50.

The spelling of 18551337449 in words is "eighteen billion, five hundred fifty-one million, three hundred thirty-seven thousand, four hundred forty-nine".