21263443 has 2 divisors, whose sum is σ = 21263444. Its totient is φ = 21263442.

The previous prime is 21263399. The next prime is 21263449. The reversal of 21263443 is 34436212.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21263443 is a prime.

It is not a weakly prime, because it can be changed into another prime (21263449) 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, 10631721 + 10631722.

It is an arithmetic number, because the mean of its divisors is an integer number (10631722).

Almost surely, 2^21263443 is an apocalyptic number.

21263443 is a deficient number, since it is larger than the sum of its proper divisors (1).

21263443 is an equidigital number, since it uses as much as digits as its factorization.

21263443 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3456, while the sum is 25.

The square root of 21263443 is about 4611.2300961891. The cubic root of 21263443 is about 277.0413080754.

Adding to 21263443 its reverse (34436212), we get a palindrome (55699655).

The spelling of 21263443 in words is "twenty-one million, two hundred sixty-three thousand, four hundred forty-three".