21444493 has 4 divisors (see below), whose sum is σ = 24508000. Its totient is φ = 18380988.

The previous prime is 21444491. The next prime is 21444499. The reversal of 21444493 is 39444412.

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 21444493 - 2¹ = 21444491 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21444491) 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, 1531743 + ... + 1531756.

It is an arithmetic number, because the mean of its divisors is an integer number (6127000).

Almost surely, 2^21444493 is an apocalyptic number.

It is an amenable number.

21444493 is a deficient number, since it is larger than the sum of its proper divisors (3063507).

21444493 is an equidigital number, since it uses as much as digits as its factorization.

21444493 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3063506.

The product of its digits is 13824, while the sum is 31.

The square root of 21444493 is about 4630.8199058050. The cubic root of 21444493 is about 277.8253867849.

The spelling of 21444493 in words is "twenty-one million, four hundred forty-four thousand, four hundred ninety-three".