20121031209 has 8 divisors (see below), whose sum is σ = 27398851200. Its totient is φ = 13128616016.

The previous prime is 20121031159. The next prime is 20121031211. The reversal of 20121031209 is 90213012102.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20121031209 - 2¹¹ = 20121029161 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20121031279) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 71351034 + ... + 71351315.

It is an arithmetic number, because the mean of its divisors is an integer number (3424856400).

Almost surely, 2^20121031209 is an apocalyptic number.

It is an amenable number.

20121031209 is a deficient number, since it is larger than the sum of its proper divisors (7277819991).

20121031209 is a wasteful number, since it uses less digits than its factorization.

20121031209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142702399.

The product of its (nonzero) digits is 216, while the sum is 21.

The spelling of 20121031209 in words is "twenty billion, one hundred twenty-one million, thirty-one thousand, two hundred nine".