20121011111209 has 4 divisors (see below), whose sum is σ = 20122457327316. Its totient is φ = 20119564895104.

The previous prime is 20121011111119. The next prime is 20121011111231. The reversal of 20121011111209 is 90211111012102.

It is a happy number.

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 5337393678400 + 14783617432809 = 2310280^2 + 3844947^2 .

It is a cyclic number.

It is not a de Polignac number, because 20121011111209 - 2¹⁹ = 20121010586921 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20121011111209.

It is not an unprimeable number, because it can be changed into a prime (20121011111809) 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 in 3 ways as a sum of consecutive naturals, for example, 723087184 + ... + 723115009.

It is an arithmetic number, because the mean of its divisors is an integer number (5030614331829).

Almost surely, 2^{20121011111209} is an apocalyptic number.

It is an amenable number.

20121011111209 is a deficient number, since it is larger than the sum of its proper divisors (1446216107).

20121011111209 is a wasteful number, since it uses less digits than its factorization.

20121011111209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1446216106.

The product of its (nonzero) digits is 72, while the sum is 22.

The spelling of 20121011111209 in words is "twenty trillion, one hundred twenty-one billion, eleven million, one hundred eleven thousand, two hundred nine".