21442312121 has 4 divisors (see below), whose sum is σ = 21805741200. Its totient is φ = 21078883044.

The previous prime is 21442312091. The next prime is 21442312147. The reversal of 21442312121 is 12121324412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21442312121 - 2⁶ = 21442312057 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21442312321) 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, 181714451 + ... + 181714568.

It is an arithmetic number, because the mean of its divisors is an integer number (5451435300).

Almost surely, 2^21442312121 is an apocalyptic number.

It is an amenable number.

21442312121 is a deficient number, since it is larger than the sum of its proper divisors (363429079).

21442312121 is an equidigital number, since it uses as much as digits as its factorization.

21442312121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 363429078.

The product of its digits is 768, while the sum is 23.

Adding to 21442312121 its reverse (12121324412), we get a palindrome (33563636533).

The spelling of 21442312121 in words is "twenty-one billion, four hundred forty-two million, three hundred twelve thousand, one hundred twenty-one".