21173741789 has 2 divisors, whose sum is σ = 21173741790. Its totient is φ = 21173741788.

The previous prime is 21173741773. The next prime is 21173741821. The reversal of 21173741789 is 98714737112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21045304900 + 128436889 = 145070^2 + 11333^2 .

It is a cyclic number.

It is not a de Polignac number, because 21173741789 - 2⁴ = 21173741773 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21173741749) 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, 10586870894 + 10586870895.

It is an arithmetic number, because the mean of its divisors is an integer number (10586870895).

Almost surely, 2^21173741789 is an apocalyptic number.

It is an amenable number.

21173741789 is a deficient number, since it is larger than the sum of its proper divisors (1).

21173741789 is an equidigital number, since it uses as much as digits as its factorization.

21173741789 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 592704, while the sum is 50.

The spelling of 21173741789 in words is "twenty-one billion, one hundred seventy-three million, seven hundred forty-one thousand, seven hundred eighty-nine".