1209689816009 has 4 divisors (see below), whose sum is σ = 1209696957204. Its totient is φ = 1209682674816.

The previous prime is 1209689815967. The next prime is 1209689816011. The reversal of 1209689816009 is 9006189869021.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 869981521984 + 339708294025 = 932728^2 + 582845^2 .

It is a cyclic number.

It is not a de Polignac number, because 1209689816009 - 2⁸ = 1209689815753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1209689816059) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3310172 + ... + 3657405.

It is an arithmetic number, because the mean of its divisors is an integer number (302424239301).

Almost surely, 2^{1209689816009} is an apocalyptic number.

It is an amenable number.

1209689816009 is a deficient number, since it is larger than the sum of its proper divisors (7141195).

1209689816009 is an equidigital number, since it uses as much as digits as its factorization.

1209689816009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7141194.

The product of its (nonzero) digits is 3359232, while the sum is 59.

The spelling of 1209689816009 in words is "one trillion, two hundred nine billion, six hundred eighty-nine million, eight hundred sixteen thousand, nine".