21103073 has 2 divisors, whose sum is σ = 21103074. Its totient is φ = 21103072.

The previous prime is 21103051. The next prime is 21103079. The reversal of 21103073 is 37030112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17447329 + 3655744 = 4177^2 + 1912^2 .

It is a cyclic number.

It is not a de Polignac number, because 21103073 - 2¹⁶ = 21037537 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21103079) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551536 + 10551537.

It is an arithmetic number, because the mean of its divisors is an integer number (10551537).

Almost surely, 2^21103073 is an apocalyptic number.

It is an amenable number.

21103073 is a deficient number, since it is larger than the sum of its proper divisors (1).

21103073 is an equidigital number, since it uses as much as digits as its factorization.

21103073 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 126, while the sum is 17.

The square root of 21103073 is about 4593.8081152787. The cubic root of 21103073 is about 276.3430630402.

Adding to 21103073 its reverse (37030112), we get a palindrome (58133185).

The spelling of 21103073 in words is "twenty-one million, one hundred three thousand, seventy-three".