21352543 has 2 divisors, whose sum is σ = 21352544. Its totient is φ = 21352542.

The previous prime is 21352531. The next prime is 21352549. The reversal of 21352543 is 34525312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21352543 - 2⁹ = 21352031 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21352549) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10676271 + 10676272.

It is an arithmetic number, because the mean of its divisors is an integer number (10676272).

Almost surely, 2^21352543 is an apocalyptic number.

21352543 is a deficient number, since it is larger than the sum of its proper divisors (1).

21352543 is an equidigital number, since it uses as much as digits as its factorization.

21352543 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3600, while the sum is 25.

The square root of 21352543 is about 4620.8811930194. The cubic root of 21352543 is about 277.4277300101.

Adding to 21352543 its reverse (34525312), we get a palindrome (55877855).

The spelling of 21352543 in words is "twenty-one million, three hundred fifty-two thousand, five hundred forty-three".