21288947489 has 2 divisors, whose sum is σ = 21288947490. Its totient is φ = 21288947488.

The previous prime is 21288947447. The next prime is 21288947503. The reversal of 21288947489 is 98474988212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19050900625 + 2238046864 = 138025^2 + 47308^2 .

It is a cyclic number.

It is not a de Polignac number, because 21288947489 - 2¹⁶ = 21288881953 is a prime.

It is not a weakly prime, because it can be changed into another prime (21288947989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10644473744 + 10644473745.

It is an arithmetic number, because the mean of its divisors is an integer number (10644473745).

Almost surely, 2^21288947489 is an apocalyptic number.

It is an amenable number.

21288947489 is a deficient number, since it is larger than the sum of its proper divisors (1).

21288947489 is an equidigital number, since it uses as much as digits as its factorization.

21288947489 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18579456, while the sum is 62.

The spelling of 21288947489 in words is "twenty-one billion, two hundred eighty-eight million, nine hundred forty-seven thousand, four hundred eighty-nine".