21001320343 has 2 divisors, whose sum is σ = 21001320344. Its totient is φ = 21001320342.

The previous prime is 21001320323. The next prime is 21001320367. The reversal of 21001320343 is 34302310012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21001320343 - 2²⁵ = 20967765911 is a prime.

It is a super-2 number, since 2×21001320343² (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 21001320343.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21001320323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500660171 + 10500660172.

It is an arithmetic number, because the mean of its divisors is an integer number (10500660172).

Almost surely, 2^21001320343 is an apocalyptic number.

21001320343 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001320343 is an equidigital number, since it uses as much as digits as its factorization.

21001320343 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 19.

Adding to 21001320343 its reverse (34302310012), we get a palindrome (55303630355).

The spelling of 21001320343 in words is "twenty-one billion, one million, three hundred twenty thousand, three hundred forty-three".