20121221011 has 8 divisors (see below), whose sum is σ = 20152533440. Its totient is φ = 20089933632.

The previous prime is 20121220981. The next prime is 20121221033. The reversal of 20121221011 is 11012212102.

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 20121221011 - 2⁵ = 20121220979 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20121220982 and 20121221000.

It is not an unprimeable number, because it can be changed into a prime (20121221041) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2128351 + ... + 2137783.

It is an arithmetic number, because the mean of its divisors is an integer number (2519066680).

Almost surely, 2^20121221011 is an apocalyptic number.

20121221011 is a deficient number, since it is larger than the sum of its proper divisors (31312429).

20121221011 is a wasteful number, since it uses less digits than its factorization.

20121221011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12525.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 20121221011 its reverse (11012212102), we get a palindrome (31133433113).

The spelling of 20121221011 in words is "twenty billion, one hundred twenty-one million, two hundred twenty-one thousand, eleven".