18906638 has 4 divisors (see below), whose sum is σ = 28359960. Its totient is φ = 9453318.

The previous prime is 18906599. The next prime is 18906659. The reversal of 18906638 is 83660981.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 83660981 = 241 ⋅347141.

It is a junction number, because it is equal to n+sod(n) for n = 18906595 and 18906604.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4726658 + ... + 4726661.

It is an arithmetic number, because the mean of its divisors is an integer number (7089990).

Almost surely, 2^18906638 is an apocalyptic number.

18906638 is a deficient number, since it is larger than the sum of its proper divisors (9453322).

18906638 is an equidigital number, since it uses as much as digits as its factorization.

18906638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9453321.

The product of its (nonzero) digits is 62208, while the sum is 41.

The square root of 18906638 is about 4348.1763993656. The cubic root of 18906638 is about 266.4023815645.

The spelling of 18906638 in words is "eighteen million, nine hundred six thousand, six hundred thirty-eight".