21287033 has 2 divisors, whose sum is σ = 21287034. Its totient is φ = 21287032.

The previous prime is 21287027. The next prime is 21287041. The reversal of 21287033 is 33078212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11377129 + 9909904 = 3373^2 + 3148^2 .

It is a cyclic number.

It is not a de Polignac number, because 21287033 - 2¹⁰ = 21286009 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21286993 and 21287011.

It is not a weakly prime, because it can be changed into another prime (21287083) 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, 10643516 + 10643517.

It is an arithmetic number, because the mean of its divisors is an integer number (10643517).

Almost surely, 2^21287033 is an apocalyptic number.

It is an amenable number.

21287033 is a deficient number, since it is larger than the sum of its proper divisors (1).

21287033 is an equidigital number, since it uses as much as digits as its factorization.

21287033 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2016, while the sum is 26.

The square root of 21287033 is about 4613.7872729462. The cubic root of 21287033 is about 277.1437215481.

The spelling of 21287033 in words is "twenty-one million, two hundred eighty-seven thousand, thirty-three".