21103003 has 2 divisors, whose sum is σ = 21103004. Its totient is φ = 21103002.

The previous prime is 21102979. The next prime is 21103021. The reversal of 21103003 is 30030112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21103003 is a prime.

It is not a weakly prime, because it can be changed into another prime (21103073) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551501 + 10551502.

It is an arithmetic number, because the mean of its divisors is an integer number (10551502).

Almost surely, 2^21103003 is an apocalyptic number.

21103003 is a deficient number, since it is larger than the sum of its proper divisors (1).

21103003 is an equidigital number, since it uses as much as digits as its factorization.

21103003 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18, while the sum is 10.

The square root of 21103003 is about 4593.8004963211. The cubic root of 21103003 is about 276.3427574917.

Adding to 21103003 its reverse (30030112), we get a palindrome (51133115).

The spelling of 21103003 in words is "twenty-one million, one hundred three thousand, three".