21358289 has 2 divisors, whose sum is σ = 21358290. Its totient is φ = 21358288.

The previous prime is 21358277. The next prime is 21358303. The reversal of 21358289 is 98285312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14025025 + 7333264 = 3745^2 + 2708^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21358289 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21358219) 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, 10679144 + 10679145.

It is an arithmetic number, because the mean of its divisors is an integer number (10679145).

Almost surely, 2^21358289 is an apocalyptic number.

It is an amenable number.

21358289 is a deficient number, since it is larger than the sum of its proper divisors (1).

21358289 is an equidigital number, since it uses as much as digits as its factorization.

21358289 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 34560, while the sum is 38.

The square root of 21358289 is about 4621.5028940811. The cubic root of 21358289 is about 277.4526131784.

The spelling of 21358289 in words is "twenty-one million, three hundred fifty-eight thousand, two hundred eighty-nine".