21903073 has 2 divisors, whose sum is σ = 21903074. Its totient is φ = 21903072.

The previous prime is 21903059. The next prime is 21903083. The reversal of 21903073 is 37030912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20142144 + 1760929 = 4488^2 + 1327^2 .

It is a cyclic number.

It is not a de Polignac number, because 21903073 - 2⁵ = 21903041 is a prime.

It is not a weakly prime, because it can be changed into another prime (21903083) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10951536 + 10951537.

It is an arithmetic number, because the mean of its divisors is an integer number (10951537).

Almost surely, 2^21903073 is an apocalyptic number.

It is an amenable number.

21903073 is a deficient number, since it is larger than the sum of its proper divisors (1).

21903073 is an equidigital number, since it uses as much as digits as its factorization.

21903073 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1134, while the sum is 25.

The square root of 21903073 is about 4680.0719011571. The cubic root of 21903073 is about 279.7918223008.

Adding to 21903073 its reverse (37030912), we get a palindrome (58933985).

The spelling of 21903073 in words is "twenty-one million, nine hundred three thousand, seventy-three".