21225461 has 4 divisors (see below), whose sum is σ = 21420300. Its totient is φ = 21030624.

The previous prime is 21225437. The next prime is 21225473. The reversal of 21225461 is 16452212.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8444836 + 12780625 = 2906^2 + 3575^2 .

It is a cyclic number.

It is not a de Polignac number, because 21225461 - 2⁶ = 21225397 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21225431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 97256 + ... + 97473.

It is an arithmetic number, because the mean of its divisors is an integer number (5355075).

Almost surely, 2^21225461 is an apocalyptic number.

It is an amenable number.

21225461 is a deficient number, since it is larger than the sum of its proper divisors (194839).

21225461 is a wasteful number, since it uses less digits than its factorization.

21225461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 194838.

The product of its digits is 960, while the sum is 23.

The square root of 21225461 is about 4607.1098315538. The cubic root of 21225461 is about 276.8762539880.

Adding to 21225461 its reverse (16452212), we get a palindrome (37677673).

The spelling of 21225461 in words is "twenty-one million, two hundred twenty-five thousand, four hundred sixty-one".