21235573 has 2 divisors, whose sum is σ = 21235574. Its totient is φ = 21235572.

The previous prime is 21235549. The next prime is 21235607. The reversal of 21235573 is 37553212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11142244 + 10093329 = 3338^2 + 3177^2 .

It is a cyclic number.

It is not a de Polignac number, because 21235573 - 2⁹ = 21235061 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21235523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10617786 + 10617787.

It is an arithmetic number, because the mean of its divisors is an integer number (10617787).

Almost surely, 2^21235573 is an apocalyptic number.

It is an amenable number.

21235573 is a deficient number, since it is larger than the sum of its proper divisors (1).

21235573 is an equidigital number, since it uses as much as digits as its factorization.

21235573 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6300, while the sum is 28.

The square root of 21235573 is about 4608.2071351015. The cubic root of 21235573 is about 276.9202157844.

Adding to 21235573 its reverse (37553212), we get a palindrome (58788785).

The spelling of 21235573 in words is "twenty-one million, two hundred thirty-five thousand, five hundred seventy-three".