20121211109 has 4 divisors (see below), whose sum is σ = 21180222240. Its totient is φ = 19062199980.

The previous prime is 20121211087. The next prime is 20121211139. The reversal of 20121211109 is 90111212102.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20121211109 - 2²⁴ = 20104433893 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121211139) 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 3 ways as a sum of consecutive naturals, for example, 529505537 + ... + 529505574.

It is an arithmetic number, because the mean of its divisors is an integer number (5295055560).

Almost surely, 2^20121211109 is an apocalyptic number.

It is an amenable number.

20121211109 is a deficient number, since it is larger than the sum of its proper divisors (1059011131).

20121211109 is a wasteful number, since it uses less digits than its factorization.

20121211109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1059011130.

The product of its (nonzero) digits is 72, while the sum is 20.

It can be divided in two parts, 2012 and 1211109, that added together give a palindrome (1213121).

The spelling of 20121211109 in words is "twenty billion, one hundred twenty-one million, two hundred eleven thousand, one hundred nine".