20011221105 has 64 divisors (see below), whose sum is σ = 33460120320. Its totient is φ = 10204185600.

The previous prime is 20011221089. The next prime is 20011221107. The reversal of 20011221105 is 50112211002.

It is not a de Polignac number, because 20011221105 - 2⁴ = 20011221089 is a prime.

It is a super-4 number, since 4×20011221105⁴ (a number of 42 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is not an unprimeable number, because it can be changed into a prime (20011221107) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 9008895 + ... + 9011115.

It is an arithmetic number, because the mean of its divisors is an integer number (522814380).

Almost surely, 2^20011221105 is an apocalyptic number.

It is an amenable number.

20011221105 is a deficient number, since it is larger than the sum of its proper divisors (13448899215).

20011221105 is a wasteful number, since it uses less digits than its factorization.

20011221105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2562.

The product of its (nonzero) digits is 40, while the sum is 15.

Adding to 20011221105 its reverse (50112211002), we get a palindrome (70123432107).

The spelling of 20011221105 in words is "twenty billion, eleven million, two hundred twenty-one thousand, one hundred five".