21736223 has 4 divisors (see below), whose sum is σ = 21746640. Its totient is φ = 21725808.

The previous prime is 21736189. The next prime is 21736229. The reversal of 21736223 is 32263712.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21736223 - 2¹⁰ = 21735199 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21736192 and 21736201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21736229) 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, 878 + ... + 6651.

It is an arithmetic number, because the mean of its divisors is an integer number (5436660).

Almost surely, 2^21736223 is an apocalyptic number.

21736223 is a deficient number, since it is larger than the sum of its proper divisors (10417).

21736223 is an equidigital number, since it uses as much as digits as its factorization.

21736223 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10416.

The product of its digits is 3024, while the sum is 26.

The square root of 21736223 is about 4662.2122431309. The cubic root of 21736223 is about 279.0795583376.

Adding to 21736223 its reverse (32263712), we get a palindrome (53999935).

The spelling of 21736223 in words is "twenty-one million, seven hundred thirty-six thousand, two hundred twenty-three".