21221325 has 48 divisors (see below), whose sum is σ = 39432000. Its totient is φ = 11188800.

The previous prime is 21221303. The next prime is 21221339. The reversal of 21221325 is 52312212.

It is not a de Polignac number, because 21221325 - 2⁵ = 21221293 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21221298 and 21221307.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 100470 + ... + 100680.

It is an arithmetic number, because the mean of its divisors is an integer number (821500).

Almost surely, 2^21221325 is an apocalyptic number.

21221325 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21221325 is a deficient number, since it is larger than the sum of its proper divisors (18210675).

21221325 is a wasteful number, since it uses less digits than its factorization.

21221325 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 379 (or 368 counting only the distinct ones).

The product of its digits is 240, while the sum is 18.

The square root of 21221325 is about 4606.6609382502. The cubic root of 21221325 is about 276.8582687551.

Adding to 21221325 its reverse (52312212), we get a palindrome (73533537).

The spelling of 21221325 in words is "twenty-one million, two hundred twenty-one thousand, three hundred twenty-five".