21342310021 has 4 divisors (see below), whose sum is σ = 21348644544. Its totient is φ = 21335975500.

The previous prime is 21342310019. The next prime is 21342310057. The reversal of 21342310021 is 12001324312.

It is a happy number.

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 21342310021 - 2¹ = 21342310019 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 (21342310321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3162205 + ... + 3168946.

It is an arithmetic number, because the mean of its divisors is an integer number (5337161136).

Almost surely, 2^21342310021 is an apocalyptic number.

It is an amenable number.

21342310021 is a deficient number, since it is larger than the sum of its proper divisors (6334523).

21342310021 is an equidigital number, since it uses as much as digits as its factorization.

21342310021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6334522.

The product of its (nonzero) digits is 288, while the sum is 19.

Adding to 21342310021 its reverse (12001324312), we get a palindrome (33343634333).

The spelling of 21342310021 in words is "twenty-one billion, three hundred forty-two million, three hundred ten thousand, twenty-one".