20121222122021 has 4 divisors (see below), whose sum is σ = 20451078222444. Its totient is φ = 19791366021600.

The previous prime is 20121222121999. The next prime is 20121222122087. The reversal of 20121222122021 is 12022122212102.

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 4800651899521 + 15320570222500 = 2191039^2 + 3914150^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20121222122021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20121222121984 and 20121222122002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121222127021) 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, 164928050120 + ... + 164928050241.

It is an arithmetic number, because the mean of its divisors is an integer number (5112769555611).

Almost surely, 2^{20121222122021} is an apocalyptic number.

It is an amenable number.

20121222122021 is a deficient number, since it is larger than the sum of its proper divisors (329856100423).

20121222122021 is an equidigital number, since it uses as much as digits as its factorization.

20121222122021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 329856100422.

The product of its (nonzero) digits is 256, while the sum is 20.

Adding to 20121222122021 its reverse (12022122212102), we get a palindrome (32143344334123).

The spelling of 20121222122021 in words is "twenty trillion, one hundred twenty-one billion, two hundred twenty-two million, one hundred twenty-two thousand, twenty-one".