18063821 has 4 divisors (see below), whose sum is σ = 18504444. Its totient is φ = 17623200.

The previous prime is 18063797. The next prime is 18063833. The reversal of 18063821 is 12836081.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12836081 = 173 ⋅74197.

It can be written as a sum of positive squares in 2 ways, for example, as 5354596 + 12709225 = 2314^2 + 3565^2 .

It is a cyclic number.

It is not a de Polignac number, because 18063821 - 2¹⁸ = 17801677 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18066821) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 220250 + ... + 220331.

It is an arithmetic number, because the mean of its divisors is an integer number (4626111).

Almost surely, 2^18063821 is an apocalyptic number.

It is an amenable number.

18063821 is a deficient number, since it is larger than the sum of its proper divisors (440623).

18063821 is an equidigital number, since it uses as much as digits as its factorization.

18063821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 440622.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 18063821 is about 4250.1554089233. The cubic root of 18063821 is about 262.3835117307.

The spelling of 18063821 in words is "eighteen million, sixty-three thousand, eight hundred twenty-one".