21043401289 has 2 divisors, whose sum is σ = 21043401290. Its totient is φ = 21043401288.

The previous prime is 21043401277. The next prime is 21043401311. The reversal of 21043401289 is 98210434012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20818161225 + 225240064 = 144285^2 + 15008^2 .

It is a cyclic number.

It is not a de Polignac number, because 21043401289 - 2¹⁷ = 21043270217 is a prime.

It is not a weakly prime, because it can be changed into another prime (21043401229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10521700644 + 10521700645.

It is an arithmetic number, because the mean of its divisors is an integer number (10521700645).

Almost surely, 2^21043401289 is an apocalyptic number.

It is an amenable number.

21043401289 is a deficient number, since it is larger than the sum of its proper divisors (1).

21043401289 is an equidigital number, since it uses as much as digits as its factorization.

21043401289 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13824, while the sum is 34.

The spelling of 21043401289 in words is "twenty-one billion, forty-three million, four hundred one thousand, two hundred eighty-nine".