18872421 has 8 divisors (see below), whose sum is σ = 25253280. Its totient is φ = 12536592.

The previous prime is 18872419. The next prime is 18872429. The reversal of 18872421 is 12427881.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18872421 - 2¹ = 18872419 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18872429) 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, 10266 + ... + 11963.

It is an arithmetic number, because the mean of its divisors is an integer number (3156660).

Almost surely, 2^18872421 is an apocalyptic number.

It is an amenable number.

18872421 is a deficient number, since it is larger than the sum of its proper divisors (6380859).

18872421 is a wasteful number, since it uses less digits than its factorization.

18872421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22515.

The product of its digits is 7168, while the sum is 33.

The square root of 18872421 is about 4344.2399795591. The cubic root of 18872421 is about 266.2415739360.

The spelling of 18872421 in words is "eighteen million, eight hundred seventy-two thousand, four hundred twenty-one".