21288959 has 2 divisors, whose sum is σ = 21288960. Its totient is φ = 21288958.

The previous prime is 21288937. The next prime is 21288973. The reversal of 21288959 is 95988212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21288959 - 2⁸ = 21288703 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21288989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10644479 + 10644480.

It is an arithmetic number, because the mean of its divisors is an integer number (10644480).

Almost surely, 2^21288959 is an apocalyptic number.

21288959 is a deficient number, since it is larger than the sum of its proper divisors (1).

21288959 is an equidigital number, since it uses as much as digits as its factorization.

21288959 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 103680, while the sum is 44.

The square root of 21288959 is about 4613.9959904621. The cubic root of 21288959 is about 277.1520797304.

The spelling of 21288959 in words is "twenty-one million, two hundred eighty-eight thousand, nine hundred fifty-nine".