21750073 has 2 divisors, whose sum is σ = 21750074. Its totient is φ = 21750072.

The previous prime is 21750059. The next prime is 21750077. The reversal of 21750073 is 37005712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15155449 + 6594624 = 3893^2 + 2568^2 .

It is a cyclic number.

It is not a de Polignac number, because 21750073 - 2⁹ = 21749561 is a prime.

It is not a weakly prime, because it can be changed into another prime (21750077) 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, 10875036 + 10875037.

It is an arithmetic number, because the mean of its divisors is an integer number (10875037).

Almost surely, 2^21750073 is an apocalyptic number.

It is an amenable number.

21750073 is a deficient number, since it is larger than the sum of its proper divisors (1).

21750073 is an equidigital number, since it uses as much as digits as its factorization.

21750073 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1470, while the sum is 25.

The square root of 21750073 is about 4663.6973529593. The cubic root of 21750073 is about 279.1388208755.

Adding to 21750073 its reverse (37005712), we get a palindrome (58755785).

The spelling of 21750073 in words is "twenty-one million, seven hundred fifty thousand, seventy-three".