21343234321 has 2 divisors, whose sum is σ = 21343234322. Its totient is φ = 21343234320.

The previous prime is 21343234303. The next prime is 21343234349. The reversal of 21343234321 is 12343234312.

It is a happy number.

It is an a-pointer prime, because the next prime (21343234349) can be obtained adding 21343234321 to its sum of digits (28).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13418673921 + 7924560400 = 115839^2 + 89020^2 .

It is a cyclic number.

It is not a de Polignac number, because 21343234321 - 2³³ = 12753299729 is a prime.

It is a super-2 number, since 2×21343234321² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21343234321.

It is not a weakly prime, because it can be changed into another prime (21343234351) 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 as a sum of consecutive naturals, namely, 10671617160 + 10671617161.

It is an arithmetic number, because the mean of its divisors is an integer number (10671617161).

Almost surely, 2^21343234321 is an apocalyptic number.

It is an amenable number.

21343234321 is a deficient number, since it is larger than the sum of its proper divisors (1).

21343234321 is an equidigital number, since it uses as much as digits as its factorization.

21343234321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10368, while the sum is 28.

Adding to 21343234321 its reverse (12343234312), we get a palindrome (33686468633).

Subtracting from 21343234321 its reverse (12343234312), we obtain a palindrome (9000000009).

The spelling of 21343234321 in words is "twenty-one billion, three hundred forty-three million, two hundred thirty-four thousand, three hundred twenty-one".