21148559 has 2 divisors, whose sum is σ = 21148560. Its totient is φ = 21148558.

The previous prime is 21148549. The next prime is 21148573. The reversal of 21148559 is 95584112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21148559 - 2²⁰ = 20099983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21148529) 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, 10574279 + 10574280.

It is an arithmetic number, because the mean of its divisors is an integer number (10574280).

Almost surely, 2^21148559 is an apocalyptic number.

21148559 is a deficient number, since it is larger than the sum of its proper divisors (1).

21148559 is an equidigital number, since it uses as much as digits as its factorization.

21148559 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14400, while the sum is 35.

The square root of 21148559 is about 4598.7562448993. The cubic root of 21148559 is about 276.5414657457.

The spelling of 21148559 in words is "twenty-one million, one hundred forty-eight thousand, five hundred fifty-nine".