21443969 has 8 divisors (see below), whose sum is σ = 21880320. Its totient is φ = 21011616.

The previous prime is 21443941. The next prime is 21443999. The reversal of 21443969 is 96934412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21443969 is a prime.

It is a super-2 number, since 2×21443969² = 919687612945922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21443999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11312 + ... + 13070.

It is an arithmetic number, because the mean of its divisors is an integer number (2735040).

Almost surely, 2^21443969 is an apocalyptic number.

It is an amenable number.

21443969 is a deficient number, since it is larger than the sum of its proper divisors (436351).

21443969 is a wasteful number, since it uses less digits than its factorization.

21443969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1999.

The product of its digits is 46656, while the sum is 38.

The square root of 21443969 is about 4630.7633280054. The cubic root of 21443969 is about 277.8231238622.

The spelling of 21443969 in words is "twenty-one million, four hundred forty-three thousand, nine hundred sixty-nine".