21256033 has 2 divisors, whose sum is σ = 21256034. Its totient is φ = 21256032.

The previous prime is 21256013. The next prime is 21256057. The reversal of 21256033 is 33065212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16184529 + 5071504 = 4023^2 + 2252^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21256033 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21255995 and 21256013.

It is not a weakly prime, because it can be changed into another prime (21256013) 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, 10628016 + 10628017.

It is an arithmetic number, because the mean of its divisors is an integer number (10628017).

Almost surely, 2^21256033 is an apocalyptic number.

It is an amenable number.

21256033 is a deficient number, since it is larger than the sum of its proper divisors (1).

21256033 is an equidigital number, since it uses as much as digits as its factorization.

21256033 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1080, while the sum is 22.

The square root of 21256033 is about 4610.4265529341. The cubic root of 21256033 is about 277.0091227169.

The spelling of 21256033 in words is "twenty-one million, two hundred fifty-six thousand, thirty-three".