18219021 has 8 divisors (see below), whose sum is σ = 24319680. Its totient is φ = 12132192.

The previous prime is 18219017. The next prime is 18219037. The reversal of 18219021 is 12091281.

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

It is not a de Polignac number, because 18219021 - 2² = 18219017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18218982 and 18219000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18219001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 160 + ... + 6038.

It is an arithmetic number, because the mean of its divisors is an integer number (3039960).

Almost surely, 2^18219021 is an apocalyptic number.

It is an amenable number.

18219021 is a deficient number, since it is larger than the sum of its proper divisors (6100659).

18219021 is a wasteful number, since it uses less digits than its factorization.

18219021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6915.

The product of its (nonzero) digits is 288, while the sum is 24.

The square root of 18219021 is about 4268.3745149647. The cubic root of 18219021 is about 263.1328151812.

The spelling of 18219021 in words is "eighteen million, two hundred nineteen thousand, twenty-one".