18421999 has 8 divisors (see below), whose sum is σ = 19616688. Its totient is φ = 17239680.

The previous prime is 18421993. The next prime is 18422003. The reversal of 18421999 is 99912481.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 18421999 - 2¹³ = 18413807 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18421993) 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 7 ways as a sum of consecutive naturals, for example, 84 + ... + 6070.

It is an arithmetic number, because the mean of its divisors is an integer number (2452086).

Almost surely, 2^18421999 is an apocalyptic number.

18421999 is a deficient number, since it is larger than the sum of its proper divisors (1194689).

18421999 is a wasteful number, since it uses less digits than its factorization.

18421999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6185.

The product of its digits is 46656, while the sum is 43.

The square root of 18421999 is about 4292.0856235634. The cubic root of 18421999 is about 264.1063955528.

The spelling of 18421999 in words is "eighteen million, four hundred twenty-one thousand, nine hundred ninety-nine".