21625321 has 4 divisors (see below), whose sum is σ = 22322944. Its totient is φ = 20927700.

The previous prime is 21625297. The next prime is 21625333. The reversal of 21625321 is 12352612.

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.

It is a cyclic number.

It is not a de Polignac number, because 21625321 - 2⁷ = 21625193 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21625292 and 21625301.

It is not an unprimeable number, because it can be changed into a prime (21625391) 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, 348765 + ... + 348826.

It is an arithmetic number, because the mean of its divisors is an integer number (5580736).

Almost surely, 2^21625321 is an apocalyptic number.

It is an amenable number.

21625321 is a deficient number, since it is larger than the sum of its proper divisors (697623).

21625321 is an equidigital number, since it uses as much as digits as its factorization.

21625321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 697622.

The product of its digits is 720, while the sum is 22.

The square root of 21625321 is about 4650.3033234403. The cubic root of 21625321 is about 278.6041112902.

Adding to 21625321 its reverse (12352612), we get a palindrome (33977933).

The spelling of 21625321 in words is "twenty-one million, six hundred twenty-five thousand, three hundred twenty-one".