21331441 has 4 divisors (see below), whose sum is σ = 22019584. Its totient is φ = 20643300.

The previous prime is 21331399. The next prime is 21331451. The reversal of 21331441 is 14413312.

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 21331441 - 2⁷ = 21331313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21331451) 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, 344025 + ... + 344086.

It is an arithmetic number, because the mean of its divisors is an integer number (5504896).

Almost surely, 2^21331441 is an apocalyptic number.

It is an amenable number.

21331441 is a deficient number, since it is larger than the sum of its proper divisors (688143).

21331441 is an equidigital number, since it uses as much as digits as its factorization.

21331441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 688142.

The product of its digits is 288, while the sum is 19.

The square root of 21331441 is about 4618.5972978817. The cubic root of 21331441 is about 277.3363090562.

Adding to 21331441 its reverse (14413312), we get a palindrome (35744753).

It can be divided in two parts, 2133144 and 1, that added together give a triangular number (2133145 = T₂₀₆₅).

The spelling of 21331441 in words is "twenty-one million, three hundred thirty-one thousand, four hundred forty-one".