21021359 has 2 divisors, whose sum is σ = 21021360. Its totient is φ = 21021358.

The previous prime is 21021349. The next prime is 21021383. The reversal of 21021359 is 95312012.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21021359 is a prime.

It is a super-3 number, since 3×21021359³ (a number of 23 digits) contains 333 as substring.

It is a Sophie Germain 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 (21021349) 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, 10510679 + 10510680.

It is an arithmetic number, because the mean of its divisors is an integer number (10510680).

Almost surely, 2^21021359 is an apocalyptic number.

21021359 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021359 is an equidigital number, since it uses as much as digits as its factorization.

21021359 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 21021359 is about 4584.9055606414. The cubic root of 21021359 is about 275.9859222323.

The spelling of 21021359 in words is "twenty-one million, twenty-one thousand, three hundred fifty-nine".