20111211121 has 4 divisors (see below), whose sum is σ = 20112939252. Its totient is φ = 20109482992.

The previous prime is 20111211119. The next prime is 20111211149. The reversal of 20111211121 is 12111211102.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12111211102 = 2 ⋅6055605551.

It can be written as a sum of positive squares in 2 ways, for example, as 1427328400 + 18683882721 = 37780^2 + 136689^2 .

It is a cyclic number.

It is not a de Polignac number, because 20111211121 - 2¹ = 20111211119 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20111211101) 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, 846490 + ... + 869923.

It is an arithmetic number, because the mean of its divisors is an integer number (5028234813).

Almost surely, 2^20111211121 is an apocalyptic number.

It is an amenable number.

20111211121 is a deficient number, since it is larger than the sum of its proper divisors (1728131).

20111211121 is a wasteful number, since it uses less digits than its factorization.

20111211121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1728130.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 20111211121 its reverse (12111211102), we get a palindrome (32222422223).

The spelling of 20111211121 in words is "twenty billion, one hundred eleven million, two hundred eleven thousand, one hundred twenty-one".