13824021 has 4 divisors (see below), whose sum is σ = 18432032. Its totient is φ = 9216012.

The previous prime is 13824017. The next prime is 13824023. The reversal of 13824021 is 12042831.

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 an emirpimes, since its reverse is a distinct semiprime: 12042831 = 3 ⋅4014277.

It is not a de Polignac number, because 13824021 - 2² = 13824017 is a prime.

It is a super-2 number, since 2×13824021² = 382207113216882, which contains 22 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 (13824023) 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 3 ways as a sum of consecutive naturals, for example, 2304001 + ... + 2304006.

It is an arithmetic number, because the mean of its divisors is an integer number (4608008).

Almost surely, 2^13824021 is an apocalyptic number.

It is an amenable number.

13824021 is a deficient number, since it is larger than the sum of its proper divisors (4608011).

13824021 is an equidigital number, since it uses as much as digits as its factorization.

13824021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4608010.

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 13824021 is about 3718.0668364084. The cubic root of 13824021 is about 240.0001215277. Note that the first 3 decimals are identical.

Subtracting from 13824021 its sum of digits (21), we obtain a cube (13824000 = 240³).

Adding to 13824021 its reverse (12042831), we get a palindrome (25866852).

The spelling of 13824021 in words is "thirteen million, eight hundred twenty-four thousand, twenty-one".