21321441 has 8 divisors (see below), whose sum is σ = 31587360. Its totient is φ = 14214276.

The previous prime is 21321431. The next prime is 21321449. The reversal of 21321441 is 14412312.

It is not a de Polignac number, because 21321441 - 2²² = 17127137 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21321449) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 394815 + ... + 394868.

It is an arithmetic number, because the mean of its divisors is an integer number (3948420).

Almost surely, 2^21321441 is an apocalyptic number.

It is an amenable number.

21321441 is a deficient number, since it is larger than the sum of its proper divisors (10265919).

21321441 is an equidigital number, since it uses as much as digits as its factorization.

21321441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 789692 (or 789686 counting only the distinct ones).

The product of its digits is 192, while the sum is 18.

The square root of 21321441 is about 4617.5145912060. The cubic root of 21321441 is about 277.2929646399.

Adding to 21321441 its reverse (14412312), we get a palindrome (35733753).

The spelling of 21321441 in words is "twenty-one million, three hundred twenty-one thousand, four hundred forty-one".