21824001 has 12 divisors (see below), whose sum is σ = 31564260. Its totient is φ = 14530560.

The previous prime is 21823981. The next prime is 21824009. The reversal of 21824001 is 10042812.

It can be written as a sum of positive squares in 2 ways, for example, as 6426225 + 15397776 = 2535^2 + 3924^2 .

It is not a de Polignac number, because 21824001 - 2⁷ = 21823873 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21824009) 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 11 ways as a sum of consecutive naturals, for example, 11821 + ... + 13541.

It is an arithmetic number, because the mean of its divisors is an integer number (2630355).

Almost surely, 2^21824001 is an apocalyptic number.

It is an amenable number.

21824001 is a deficient number, since it is larger than the sum of its proper divisors (9740259).

21824001 is a wasteful number, since it uses less digits than its factorization.

21824001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3136 (or 3133 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The square root of 21824001 is about 4671.6165296394. The cubic root of 21824001 is about 279.4547253810.

Adding to 21824001 its reverse (10042812), we get a palindrome (31866813).

The spelling of 21824001 in words is "twenty-one million, eight hundred twenty-four thousand, one".