21223493 has 8 divisors (see below), whose sum is σ = 21520800. Its totient is φ = 20928528.

The previous prime is 21223487. The next prime is 21223507. The reversal of 21223493 is 39432212.

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

It is a cyclic number.

It is not a de Polignac number, because 21223493 - 2¹⁰ = 21222469 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 (21223403) 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, 24455 + ... + 25307.

It is an arithmetic number, because the mean of its divisors is an integer number (2690100).

Almost surely, 2^21223493 is an apocalyptic number.

It is an amenable number.

21223493 is a deficient number, since it is larger than the sum of its proper divisors (297307).

21223493 is a wasteful number, since it uses less digits than its factorization.

21223493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1171.

The product of its digits is 2592, while the sum is 26.

The square root of 21223493 is about 4606.8962436764. The cubic root of 21223493 is about 276.8676965090.

The spelling of 21223493 in words is "twenty-one million, two hundred twenty-three thousand, four hundred ninety-three".