18871849 has 4 divisors (see below), whose sum is σ = 19332180. Its totient is φ = 18411520.

The previous prime is 18871841. The next prime is 18871859. The reversal of 18871849 is 94817881.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 94817881 = 43 ⋅2205067.

It can be written as a sum of positive squares in 2 ways, for example, as 1607824 + 17264025 = 1268^2 + 4155^2 .

It is a cyclic number.

It is not a de Polignac number, because 18871849 - 2³ = 18871841 is a prime.

It is a super-2 number, since 2×18871849² = 712293369357602, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18871799 and 18871808.

It is not an unprimeable number, because it can be changed into a prime (18871841) 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, 230104 + ... + 230185.

It is an arithmetic number, because the mean of its divisors is an integer number (4833045).

Almost surely, 2^18871849 is an apocalyptic number.

It is an amenable number.

18871849 is a deficient number, since it is larger than the sum of its proper divisors (460331).

18871849 is an equidigital number, since it uses as much as digits as its factorization.

18871849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 460330.

The product of its digits is 129024, while the sum is 46.

The square root of 18871849 is about 4344.1741447599. The cubic root of 18871849 is about 266.2388840900.

The spelling of 18871849 in words is "eighteen million, eight hundred seventy-one thousand, eight hundred forty-nine".