21748423 has 4 divisors (see below), whose sum is σ = 23027760. Its totient is φ = 20469088.

The previous prime is 21748421. The next prime is 21748427. The reversal of 21748423 is 32484712.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21748423 - 2¹ = 21748421 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 (21748421) 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, 639643 + ... + 639676.

It is an arithmetic number, because the mean of its divisors is an integer number (5756940).

Almost surely, 2^21748423 is an apocalyptic number.

21748423 is a deficient number, since it is larger than the sum of its proper divisors (1279337).

21748423 is a wasteful number, since it uses less digits than its factorization.

21748423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1279336.

The product of its digits is 10752, while the sum is 31.

The square root of 21748423 is about 4663.5204513329. The cubic root of 21748423 is about 279.1317620378.

The spelling of 21748423 in words is "twenty-one million, seven hundred forty-eight thousand, four hundred twenty-three".