21504230 has 16 divisors (see below), whose sum is σ = 42226704. Its totient is φ = 7819680.

The previous prime is 21504227. The next prime is 21504233. The reversal of 21504230 is 3240512.

It is an interprime number because it is at equal distance from previous prime (21504227) and next prime (21504233).

It is a junction number, because it is equal to n+sod(n) for n = 21504199 and 21504208.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21504233) 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, 97637 + ... + 97856.

It is an arithmetic number, because the mean of its divisors is an integer number (2639169).

Almost surely, 2^21504230 is an apocalyptic number.

21504230 is a deficient number, since it is larger than the sum of its proper divisors (20722474).

21504230 is a wasteful number, since it uses less digits than its factorization.

21504230 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195511.

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 21504230 is about 4637.2653579453. The cubic root of 21504230 is about 278.0831230136.

Adding to 21504230 its reverse (3240512), we get a palindrome (24744742).

The spelling of 21504230 in words is "twenty-one million, five hundred four thousand, two hundred thirty".