21225441 has 4 divisors (see below), whose sum is σ = 28300592. Its totient is φ = 14150292.

The previous prime is 21225437. The next prime is 21225473. The reversal of 21225441 is 14452212.

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 not a de Polignac number, because 21225441 - 2² = 21225437 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21225431) 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, 3537571 + ... + 3537576.

It is an arithmetic number, because the mean of its divisors is an integer number (7075148).

Almost surely, 2^21225441 is an apocalyptic number.

It is an amenable number.

21225441 is a deficient number, since it is larger than the sum of its proper divisors (7075151).

21225441 is an equidigital number, since it uses as much as digits as its factorization.

21225441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7075150.

The product of its digits is 640, while the sum is 21.

The square root of 21225441 is about 4607.1076609951. The cubic root of 21225441 is about 276.8761670244.

Adding to 21225441 its reverse (14452212), we get a palindrome (35677653).

The spelling of 21225441 in words is "twenty-one million, two hundred twenty-five thousand, four hundred forty-one".