21445441 has 2 divisors, whose sum is σ = 21445442. Its totient is φ = 21445440.

The previous prime is 21445409. The next prime is 21445451. The reversal of 21445441 is 14454412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17850625 + 3594816 = 4225^2 + 1896^2 .

It is a cyclic number.

It is not a de Polignac number, because 21445441 - 2⁵ = 21445409 is a prime.

It is not a weakly prime, because it can be changed into another prime (21445451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10722720 + 10722721.

It is an arithmetic number, because the mean of its divisors is an integer number (10722721).

Almost surely, 2^21445441 is an apocalyptic number.

It is an amenable number.

21445441 is a deficient number, since it is larger than the sum of its proper divisors (1).

21445441 is an equidigital number, since it uses as much as digits as its factorization.

21445441 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2560, while the sum is 25.

The square root of 21445441 is about 4630.9222623577. The cubic root of 21445441 is about 277.8294806811.

Adding to 21445441 its reverse (14454412), we get a palindrome (35899853).

The spelling of 21445441 in words is "twenty-one million, four hundred forty-five thousand, four hundred forty-one".