21523433 has 2 divisors, whose sum is σ = 21523434. Its totient is φ = 21523432.

The previous prime is 21523421. The next prime is 21523499. The reversal of 21523433 is 33432512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15031129 + 6492304 = 3877^2 + 2548^2 .

It is a cyclic number.

It is not a de Polignac number, because 21523433 - 2⁴ = 21523417 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21523399 and 21523408.

It is not a weakly prime, because it can be changed into another prime (21528433) 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, 10761716 + 10761717.

It is an arithmetic number, because the mean of its divisors is an integer number (10761717).

Almost surely, 2^21523433 is an apocalyptic number.

It is an amenable number.

21523433 is a deficient number, since it is larger than the sum of its proper divisors (1).

21523433 is an equidigital number, since it uses as much as digits as its factorization.

21523433 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2160, while the sum is 23.

The square root of 21523433 is about 4639.3354049907. The cubic root of 21523433 is about 278.1658732675.

Adding to 21523433 its reverse (33432512), we get a palindrome (54955945).

The spelling of 21523433 in words is "twenty-one million, five hundred twenty-three thousand, four hundred thirty-three".