18978423 has 4 divisors (see below), whose sum is σ = 25304568. Its totient is φ = 12652280.

The previous prime is 18978419. The next prime is 18978439. The reversal of 18978423 is 32487981.

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

It is a cyclic number.

It is not a de Polignac number, because 18978423 - 2² = 18978419 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18978403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3163068 + ... + 3163073.

It is an arithmetic number, because the mean of its divisors is an integer number (6326142).

Almost surely, 2^18978423 is an apocalyptic number.

18978423 is a deficient number, since it is larger than the sum of its proper divisors (6326145).

18978423 is an equidigital number, since it uses as much as digits as its factorization.

18978423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6326144.

The product of its digits is 96768, while the sum is 42.

The square root of 18978423 is about 4356.4231888098. The cubic root of 18978423 is about 266.7391159051.

The spelling of 18978423 in words is "eighteen million, nine hundred seventy-eight thousand, four hundred twenty-three".