21723203 has 2 divisors, whose sum is σ = 21723204. Its totient is φ = 21723202.

The previous prime is 21723197. The next prime is 21723211. The reversal of 21723203 is 30232712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21723203 - 2⁴ = 21723187 is a prime.

It is a plaindrome in base 13.

It is not a weakly prime, because it can be changed into another prime (21723253) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10861601 + 10861602.

It is an arithmetic number, because the mean of its divisors is an integer number (10861602).

Almost surely, 2^21723203 is an apocalyptic number.

21723203 is a deficient number, since it is larger than the sum of its proper divisors (1).

21723203 is an equidigital number, since it uses as much as digits as its factorization.

21723203 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 504, while the sum is 20.

The square root of 21723203 is about 4660.8157011407. The cubic root of 21723203 is about 279.0238243124.

Adding to 21723203 its reverse (30232712), we get a palindrome (51955915).

The spelling of 21723203 in words is "twenty-one million, seven hundred twenty-three thousand, two hundred three".