20101221011 has 4 divisors (see below), whose sum is σ = 20139655992. Its totient is φ = 20062786032.

The previous prime is 20101220987. The next prime is 20101221043. The reversal of 20101221011 is 11012210102.

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 20101221011 - 2²² = 20097026707 is a prime.

It is a super-2 number, since 2×20101221011² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20101220983 and 20101221001.

It is not an unprimeable number, because it can be changed into a prime (20101221061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19216706 + ... + 19217751.

It is an arithmetic number, because the mean of its divisors is an integer number (5034913998).

Almost surely, 2^20101221011 is an apocalyptic number.

20101221011 is a deficient number, since it is larger than the sum of its proper divisors (38434981).

20101221011 is an equidigital number, since it uses as much as digits as its factorization.

20101221011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38434980.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 20101221011 its reverse (11012210102), we get a palindrome (31113431113).

The spelling of 20101221011 in words is "twenty billion, one hundred one million, two hundred twenty-one thousand, eleven".