21284933 has 2 divisors, whose sum is σ = 21284934. Its totient is φ = 21284932.

The previous prime is 21284929. The next prime is 21284947. The reversal of 21284933 is 33948212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20367169 + 917764 = 4513^2 + 958^2 .

It is a cyclic number.

It is not a de Polignac number, because 21284933 - 2² = 21284929 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21284933.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21284903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10642466 + 10642467.

It is an arithmetic number, because the mean of its divisors is an integer number (10642467).

Almost surely, 2^21284933 is an apocalyptic number.

It is an amenable number.

21284933 is a deficient number, since it is larger than the sum of its proper divisors (1).

21284933 is an equidigital number, since it uses as much as digits as its factorization.

21284933 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10368, while the sum is 32.

The square root of 21284933 is about 4613.5596885702. The cubic root of 21284933 is about 277.1346076906.

The spelling of 21284933 in words is "twenty-one million, two hundred eighty-four thousand, nine hundred thirty-three".