20121134491 has 4 divisors (see below), whose sum is σ = 20500778592. Its totient is φ = 19741490392.

The previous prime is 20121134477. The next prime is 20121134503. The reversal of 20121134491 is 19443112102.

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 20121134491 - 2¹¹ = 20121132443 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20121134401) 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, 189821971 + ... + 189822076.

It is an arithmetic number, because the mean of its divisors is an integer number (5125194648).

Almost surely, 2^20121134491 is an apocalyptic number.

20121134491 is a deficient number, since it is larger than the sum of its proper divisors (379644101).

20121134491 is an equidigital number, since it uses as much as digits as its factorization.

20121134491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 379644100.

The product of its (nonzero) digits is 1728, while the sum is 28.

Adding to 20121134491 its reverse (19443112102), we get a palindrome (39564246593).

The spelling of 20121134491 in words is "twenty billion, one hundred twenty-one million, one hundred thirty-four thousand, four hundred ninety-one".