1231011209789 has 2 divisors, whose sum is σ = 1231011209790. Its totient is φ = 1231011209788.

The previous prime is 1231011209719. The next prime is 1231011209801. The reversal of 1231011209789 is 9879021101321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1017990192025 + 213021017764 = 1008955^2 + 461542^2 .

It is a cyclic number.

It is not a de Polignac number, because 1231011209789 - 2¹² = 1231011205693 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 (1231011209719) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615505604894 + 615505604895.

It is an arithmetic number, because the mean of its divisors is an integer number (615505604895).

Almost surely, 2^{1231011209789} is an apocalyptic number.

It is an amenable number.

1231011209789 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231011209789 is an equidigital number, since it uses as much as digits as its factorization.

1231011209789 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54432, while the sum is 44.

The spelling of 1231011209789 in words is "one trillion, two hundred thirty-one billion, eleven million, two hundred nine thousand, seven hundred eighty-nine".