21103223 has 4 divisors (see below), whose sum is σ = 21320880. Its totient is φ = 20885568.

The previous prime is 21103217. The next prime is 21103241. The reversal of 21103223 is 32230112.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21103223 - 2⁴ = 21103207 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21103198 and 21103207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21103253) 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, 108683 + ... + 108876.

It is an arithmetic number, because the mean of its divisors is an integer number (5330220).

It is a self-describing number.

Almost surely, 2^21103223 is an apocalyptic number.

21103223 is a deficient number, since it is larger than the sum of its proper divisors (217657).

21103223 is an equidigital number, since it uses as much as digits as its factorization.

21103223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217656.

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 21103223 is about 4593.8244415737. The cubic root of 21103223 is about 276.3437177846.

Adding to 21103223 its reverse (32230112), we get a palindrome (53333335).

The spelling of 21103223 in words is "twenty-one million, one hundred three thousand, two hundred twenty-three".