18421917 has 8 divisors (see below), whose sum is σ = 24628224. Its totient is φ = 12248448.

The previous prime is 18421891. The next prime is 18421943. The reversal of 18421917 is 71912481.

It is an interprime number because it is at equal distance from previous prime (18421891) and next prime (18421943).

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

It is not a de Polignac number, because 18421917 - 2⁶ = 18421853 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18421987) by changing a digit.

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 in 7 ways as a sum of consecutive naturals, for example, 6868 + ... + 9165.

It is an arithmetic number, because the mean of its divisors is an integer number (3078528).

Almost surely, 2^18421917 is an apocalyptic number.

It is an amenable number.

18421917 is a deficient number, since it is larger than the sum of its proper divisors (6206307).

18421917 is a wasteful number, since it uses less digits than its factorization.

18421917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16419.

The product of its digits is 4032, while the sum is 33.

The square root of 18421917 is about 4292.0760710873. The cubic root of 18421917 is about 264.1060036888.

The spelling of 18421917 in words is "eighteen million, four hundred twenty-one thousand, nine hundred seventeen".