21443493 has 4 divisors (see below), whose sum is σ = 28591328. Its totient is φ = 14295660.

The previous prime is 21443483. The next prime is 21443497. The reversal of 21443493 is 39434412.

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 not a de Polignac number, because 21443493 - 2¹⁶ = 21377957 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21443493.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21443497) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3573913 + ... + 3573918.

It is an arithmetic number, because the mean of its divisors is an integer number (7147832).

Almost surely, 2^21443493 is an apocalyptic number.

It is an amenable number.

21443493 is a deficient number, since it is larger than the sum of its proper divisors (7147835).

21443493 is an equidigital number, since it uses as much as digits as its factorization.

21443493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7147834.

The product of its digits is 10368, while the sum is 30.

The square root of 21443493 is about 4630.7119323059. The cubic root of 21443493 is about 277.8210681982.

The spelling of 21443493 in words is "twenty-one million, four hundred forty-three thousand, four hundred ninety-three".