21003223 has 2 divisors, whose sum is σ = 21003224. Its totient is φ = 21003222.

The previous prime is 21003179. The next prime is 21003247. The reversal of 21003223 is 32230012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21003223 - 2⁹ = 21002711 is a prime.

It is a super-2 number, since 2×21003223² = 882270752775458, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21003293) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501611 + 10501612.

It is an arithmetic number, because the mean of its divisors is an integer number (10501612).

Almost surely, 2^21003223 is an apocalyptic number.

21003223 is a deficient number, since it is larger than the sum of its proper divisors (1).

21003223 is an equidigital number, since it uses as much as digits as its factorization.

21003223 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 13.

The square root of 21003223 is about 4582.9273395942. The cubic root of 21003223 is about 275.9065312219.

Adding to 21003223 its reverse (32230012), we get a palindrome (53233235).

The spelling of 21003223 in words is "twenty-one million, three thousand, two hundred twenty-three".