20121121022221 has 4 divisors (see below), whose sum is σ = 20193760448572. Its totient is φ = 20048481595872.

The previous prime is 20121121022209. The next prime is 20121121022237. The reversal of 20121121022221 is 12222012112102.

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 3503676419721 + 16617444602500 = 1871811^2 + 4076450^2 .

It is a cyclic number.

It is not a de Polignac number, because 20121121022221 - 2¹¹ = 20121121020173 is a prime.

It is a super-2 number, since 2×20121121022221² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121121023221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36319712760 + ... + 36319713313.

It is an arithmetic number, because the mean of its divisors is an integer number (5048440112143).

Almost surely, 2^{20121121022221} is an apocalyptic number.

It is an amenable number.

20121121022221 is a deficient number, since it is larger than the sum of its proper divisors (72639426351).

20121121022221 is an equidigital number, since it uses as much as digits as its factorization.

20121121022221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72639426350.

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 20121121022221 its reverse (12222012112102), we get a palindrome (32343133134323).

The spelling of 20121121022221 in words is "twenty trillion, one hundred twenty-one billion, one hundred twenty-one million, twenty-two thousand, two hundred twenty-one".