2121220000021 has 4 divisors (see below), whose sum is σ = 2155994098444. Its totient is φ = 2086445901600.

The previous prime is 2121220000007. The next prime is 2121220000049. The reversal of 2121220000021 is 1200000221212.

It is a happy number.

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 956309923921 + 1164910076100 = 977911^2 + 1079310^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121220000021 - 2¹¹ = 2121219997973 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2121219999956 and 2121220000010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121220000091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17387049120 + ... + 17387049241.

It is an arithmetic number, because the mean of its divisors is an integer number (538998524611).

Almost surely, 2^{2121220000021} is an apocalyptic number.

It is an amenable number.

2121220000021 is a deficient number, since it is larger than the sum of its proper divisors (34774098423).

2121220000021 is an equidigital number, since it uses as much as digits as its factorization.

2121220000021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34774098422.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 2121220000021 its reverse (1200000221212), we get a palindrome (3321220221233).

The spelling of 2121220000021 in words is "two trillion, one hundred twenty-one billion, two hundred twenty million, twenty-one", and thus it is an aban number.