20121131011 has 4 divisors (see below), whose sum is σ = 20121579352. Its totient is φ = 20120682672.

The previous prime is 20121130999. The next prime is 20121131053. The reversal of 20121131011 is 11013112102.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 20121131011 - 2⁹ = 20121130499 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20121130982 and 20121131000.

It is not an unprimeable number, because it can be changed into a prime (20121131111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 148290 + ... + 249463.

It is an arithmetic number, because the mean of its divisors is an integer number (5030394838).

Almost surely, 2^20121131011 is an apocalyptic number.

20121131011 is a deficient number, since it is larger than the sum of its proper divisors (448341).

20121131011 is an equidigital number, since it uses as much as digits as its factorization.

20121131011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 448340.

The product of its (nonzero) digits is 12, while the sum is 13.

Adding to 20121131011 its reverse (11013112102), we get a palindrome (31134243113).

The spelling of 20121131011 in words is "twenty billion, one hundred twenty-one million, one hundred thirty-one thousand, eleven".