21253103 has 2 divisors, whose sum is σ = 21253104. Its totient is φ = 21253102.

The previous prime is 21253093. The next prime is 21253109. The reversal of 21253103 is 30135212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21253103 - 2¹⁰ = 21252079 is a prime.

It is a Chen prime.

It is a plaindrome in base 16.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21253109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10626551 + 10626552.

It is an arithmetic number, because the mean of its divisors is an integer number (10626552).

Almost surely, 2^21253103 is an apocalyptic number.

21253103 is a deficient number, since it is larger than the sum of its proper divisors (1).

21253103 is an equidigital number, since it uses as much as digits as its factorization.

21253103 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 180, while the sum is 17.

The square root of 21253103 is about 4610.1087839659. The cubic root of 21253103 is about 276.9963941891.

Adding to 21253103 its reverse (30135212), we get a palindrome (51388315).

The spelling of 21253103 in words is "twenty-one million, two hundred fifty-three thousand, one hundred three".