21065284789 has 2 divisors, whose sum is σ = 21065284790. Its totient is φ = 21065284788.

The previous prime is 21065284727. The next prime is 21065284829. The reversal of 21065284789 is 98748256012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17947960900 + 3117323889 = 133970^2 + 55833^2 .

It is a cyclic number.

It is not a de Polignac number, because 21065284789 - 2²³ = 21056896181 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21065284489) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10532642394 + 10532642395.

It is an arithmetic number, because the mean of its divisors is an integer number (10532642395).

Almost surely, 2^21065284789 is an apocalyptic number.

It is an amenable number.

21065284789 is a deficient number, since it is larger than the sum of its proper divisors (1).

21065284789 is an equidigital number, since it uses as much as digits as its factorization.

21065284789 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1935360, while the sum is 52.

The spelling of 21065284789 in words is "twenty-one billion, sixty-five million, two hundred eighty-four thousand, seven hundred eighty-nine".