21389359 has 2 divisors, whose sum is σ = 21389360. Its totient is φ = 21389358.

The previous prime is 21389353. The next prime is 21389363. The reversal of 21389359 is 95398312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21389359 - 2³ = 21389351 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21389351) 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, 10694679 + 10694680.

It is an arithmetic number, because the mean of its divisors is an integer number (10694680).

Almost surely, 2^21389359 is an apocalyptic number.

21389359 is a deficient number, since it is larger than the sum of its proper divisors (1).

21389359 is an equidigital number, since it uses as much as digits as its factorization.

21389359 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 58320, while the sum is 40.

The square root of 21389359 is about 4624.8631331100. The cubic root of 21389359 is about 277.5870851859.

The spelling of 21389359 in words is "twenty-one million, three hundred eighty-nine thousand, three hundred fifty-nine".