18824221 has 8 divisors (see below), whose sum is σ = 20321280. Its totient is φ = 17334192.

The previous prime is 18824209. The next prime is 18824233. The reversal of 18824221 is 12242881.

It is an interprime number because it is at equal distance from previous prime (18824209) and next prime (18824233).

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 18824221 - 2⁷ = 18824093 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18824221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18824261) 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, 4716 + ... + 7738.

It is an arithmetic number, because the mean of its divisors is an integer number (2540160).

Almost surely, 2^18824221 is an apocalyptic number.

It is an amenable number.

18824221 is a deficient number, since it is larger than the sum of its proper divisors (1497059).

18824221 is a wasteful number, since it uses less digits than its factorization.

18824221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3515.

The product of its digits is 2048, while the sum is 28.

The square root of 18824221 is about 4338.6888572471. The cubic root of 18824221 is about 266.0147211405.

The spelling of 18824221 in words is "eighteen million, eight hundred twenty-four thousand, two hundred twenty-one".