21123103 has 2 divisors, whose sum is σ = 21123104. Its totient is φ = 21123102.

The previous prime is 21123073. The next prime is 21123119. The reversal of 21123103 is 30132112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21123103 - 2¹³ = 21114911 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21123133) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561551 + 10561552.

It is an arithmetic number, because the mean of its divisors is an integer number (10561552).

Almost surely, 2^21123103 is an apocalyptic number.

21123103 is a deficient number, since it is larger than the sum of its proper divisors (1).

21123103 is an equidigital number, since it uses as much as digits as its factorization.

21123103 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36, while the sum is 13.

The square root of 21123103 is about 4595.9877066850. The cubic root of 21123103 is about 276.4304658123.

Adding to 21123103 its reverse (30132112), we get a palindrome (51255215).

Subtracting 21123103 from its reverse (30132112), we obtain a palindrome (9009009).

The spelling of 21123103 in words is "twenty-one million, one hundred twenty-three thousand, one hundred three".