21335389 has 2 divisors, whose sum is σ = 21335390. Its totient is φ = 21335388.

The previous prime is 21335359. The next prime is 21335411. The reversal of 21335389 is 98353312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21068100 + 267289 = 4590^2 + 517^2 .

It is a cyclic number.

It is not a de Polignac number, because 21335389 - 2⁷ = 21335261 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21335339) 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, 10667694 + 10667695.

It is an arithmetic number, because the mean of its divisors is an integer number (10667695).

Almost surely, 2^21335389 is an apocalyptic number.

It is an amenable number.

21335389 is a deficient number, since it is larger than the sum of its proper divisors (1).

21335389 is an equidigital number, since it uses as much as digits as its factorization.

21335389 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 19440, while the sum is 34.

The square root of 21335389 is about 4619.0246806009. The cubic root of 21335389 is about 277.3534177020.

The spelling of 21335389 in words is "twenty-one million, three hundred thirty-five thousand, three hundred eighty-nine".