22121121220021 has 4 divisors (see below), whose sum is σ = 22883918503500. Its totient is φ = 21358323936544.

The previous prime is 22121121220001. The next prime is 22121121220027. The reversal of 22121121220021 is 12002212112122.

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 8578537219396 + 13542584000625 = 2928914^2 + 3680025^2 .

It is a cyclic number.

It is not a de Polignac number, because 22121121220021 - 2¹⁹ = 22121120695733 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22121121220027) 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, 381398641696 + ... + 381398641753.

It is an arithmetic number, because the mean of its divisors is an integer number (5720979625875).

Almost surely, 2^{22121121220021} is an apocalyptic number.

It is an amenable number.

22121121220021 is a deficient number, since it is larger than the sum of its proper divisors (762797283479).

22121121220021 is an equidigital number, since it uses as much as digits as its factorization.

22121121220021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 762797283478.

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

Adding to 22121121220021 its reverse (12002212112122), we get a palindrome (34123333332143).

The spelling of 22121121220021 in words is "twenty-two trillion, one hundred twenty-one billion, one hundred twenty-one million, two hundred twenty thousand, twenty-one".