20101221111221 has 4 divisors (see below), whose sum is σ = 20101265019372. Its totient is φ = 20101177203072.

The previous prime is 20101221111193. The next prime is 20101221111241. The reversal of 20101221111221 is 12211112210102.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13381798036996 + 6719423074225 = 3658114^2 + 2592185^2 .

It is a cyclic number.

It is not a de Polignac number, because 20101221111221 - 2⁴² = 15703174600117 is a prime.

It is a super-2 number, since 2×20101221111221² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20101221111221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20101221111241) 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, 21260060 + ... + 22185413.

It is an arithmetic number, because the mean of its divisors is an integer number (5025316254843).

Almost surely, 2^{20101221111221} is an apocalyptic number.

It is an amenable number.

20101221111221 is a deficient number, since it is larger than the sum of its proper divisors (43908151).

20101221111221 is an equidigital number, since it uses as much as digits as its factorization.

20101221111221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43908150.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 20101221111221 its reverse (12211112210102), we get a palindrome (32312333321323).

The spelling of 20101221111221 in words is "twenty trillion, one hundred one billion, two hundred twenty-one million, one hundred eleven thousand, two hundred twenty-one".