2121200231221 has 4 divisors (see below), whose sum is σ = 2121208991500. Its totient is φ = 2121191470944.

The previous prime is 2121200231209. The next prime is 2121200231261. The reversal of 2121200231221 is 1221320021212.

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 1134734127121 + 986466104100 = 1065239^2 + 993210^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2121200231221 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 (2121200231201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4006296 + ... + 4504753.

It is an arithmetic number, because the mean of its divisors is an integer number (530302247875).

Almost surely, 2^{2121200231221} is an apocalyptic number.

It is an amenable number.

2121200231221 is a deficient number, since it is larger than the sum of its proper divisors (8760279).

2121200231221 is an equidigital number, since it uses as much as digits as its factorization.

2121200231221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8760278.

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 2121200231221 its reverse (1221320021212), we get a palindrome (3342520252433).

The spelling of 2121200231221 in words is "two trillion, one hundred twenty-one billion, two hundred million, two hundred thirty-one thousand, two hundred twenty-one".