21300289 has 2 divisors, whose sum is σ = 21300290. Its totient is φ = 21300288.

The previous prime is 21300287. The next prime is 21300319. The reversal of 21300289 is 98200312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20930625 + 369664 = 4575^2 + 608^2 .

It is a cyclic number.

It is not a de Polignac number, because 21300289 - 2¹ = 21300287 is a prime.

It is a super-2 number, since 2×21300289² = 907404622967042, which contains 22 as substring.

Together with 21300287, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21300287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10650144 + 10650145.

It is an arithmetic number, because the mean of its divisors is an integer number (10650145).

Almost surely, 2^21300289 is an apocalyptic number.

It is an amenable number.

21300289 is a deficient number, since it is larger than the sum of its proper divisors (1).

21300289 is an equidigital number, since it uses as much as digits as its factorization.

21300289 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 21300289 is about 4615.2236132175. The cubic root of 21300289 is about 277.2012378593.

The spelling of 21300289 in words is "twenty-one million, three hundred thousand, two hundred eighty-nine".