18282821 has 4 divisors (see below), whose sum is σ = 18294144. Its totient is φ = 18271500.

The previous prime is 18282791. The next prime is 18282833. The reversal of 18282821 is 12828281.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 12828281 = 233 ⋅55057.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18282821 is a prime.

It is a super-3 number, since 3×18282821³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18282841) 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 3 ways as a sum of consecutive naturals, for example, 2735 + ... + 6636.

It is an arithmetic number, because the mean of its divisors is an integer number (4573536).

Almost surely, 2^18282821 is an apocalyptic number.

It is an amenable number.

18282821 is a deficient number, since it is larger than the sum of its proper divisors (11323).

18282821 is an equidigital number, since it uses as much as digits as its factorization.

18282821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11322.

The product of its digits is 4096, while the sum is 32.

The square root of 18282821 is about 4275.8415545948. The cubic root of 18282821 is about 263.4396065564.

The spelling of 18282821 in words is "eighteen million, two hundred eighty-two thousand, eight hundred twenty-one".