21052243 has 2 divisors, whose sum is σ = 21052244. Its totient is φ = 21052242.

The previous prime is 21052219. The next prime is 21052253. The reversal of 21052243 is 34225012.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21052243 is a prime.

It is a super-3 number, since 3×21052243³ (a number of 23 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21052243.

It is not a weakly prime, because it can be changed into another prime (21052253) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10526121 + 10526122.

It is an arithmetic number, because the mean of its divisors is an integer number (10526122).

Almost surely, 2^21052243 is an apocalyptic number.

21052243 is a deficient number, since it is larger than the sum of its proper divisors (1).

21052243 is an equidigital number, since it uses as much as digits as its factorization.

21052243 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 21052243 is about 4588.2723328068. The cubic root of 21052243 is about 276.1210130613.

Adding to 21052243 its reverse (34225012), we get a palindrome (55277255).

The spelling of 21052243 in words is "twenty-one million, fifty-two thousand, two hundred forty-three".