21210103 has 2 divisors, whose sum is σ = 21210104. Its totient is φ = 21210102.

The previous prime is 21210097. The next prime is 21210109. The reversal of 21210103 is 30101212.

It is a balanced prime because it is at equal distance from previous prime (21210097) and next prime (21210109).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21210103 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a self number, because there is not a number n which added to its sum of digits gives 21210103.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21210109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605051 + 10605052.

It is an arithmetic number, because the mean of its divisors is an integer number (10605052).

Almost surely, 2^21210103 is an apocalyptic number.

21210103 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210103 is an equidigital number, since it uses as much as digits as its factorization.

21210103 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12, while the sum is 10.

The square root of 21210103 is about 4605.4427583024. The cubic root of 21210103 is about 276.8094585559.

Adding to 21210103 its reverse (30101212), we get a palindrome (51311315).

The spelling of 21210103 in words is "twenty-one million, two hundred ten thousand, one hundred three".