18871138 has 16 divisors (see below), whose sum is σ = 33255936. Its totient is φ = 7917840.

The previous prime is 18871133. The next prime is 18871183. The reversal of 18871138 is 83117881.

It is a super-2 number, since 2×18871138² = 712239698830088, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 18871097 and 18871106.

It is not an unprimeable number, because it can be changed into a prime (18871133) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32706 + ... + 33277.

It is an arithmetic number, because the mean of its divisors is an integer number (2078496).

Almost surely, 2^18871138 is an apocalyptic number.

18871138 is a deficient number, since it is larger than the sum of its proper divisors (14384798).

18871138 is a wasteful number, since it uses less digits than its factorization.

18871138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66009.

The product of its digits is 10752, while the sum is 37.

The square root of 18871138 is about 4344.0923102531. The cubic root of 18871138 is about 266.2355405168.

It can be divided in two parts, 1887 and 1138, that added together give a square (3025 = 55²).

The spelling of 18871138 in words is "eighteen million, eight hundred seventy-one thousand, one hundred thirty-eight".