21020340343321 has 16 divisors (see below), whose sum is σ = 23590780536960. Its totient is φ = 18566817909120.

The previous prime is 21020340343297. The next prime is 21020340343333. The reversal of 21020340343321 is 12334304302012.

It is a happy number.

It is not a de Polignac number, because 21020340343321 - 2⁷ = 21020340343193 is a prime.

It is a super-2 number, since 2×21020340343321² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21020340343321.

It is not an unprimeable number, because it can be changed into a prime (21020340343381) 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 15 ways as a sum of consecutive naturals, for example, 174966516 + ... + 175086613.

It is an arithmetic number, because the mean of its divisors is an integer number (1474423783560).

Almost surely, 2^{21020340343321} is an apocalyptic number.

It is an amenable number.

21020340343321 is a deficient number, since it is larger than the sum of its proper divisors (2570440193639).

21020340343321 is a wasteful number, since it uses less digits than its factorization.

21020340343321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 350053296.

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

Adding to 21020340343321 its reverse (12334304302012), we get a palindrome (33354644645333).

The spelling of 21020340343321 in words is "twenty-one trillion, twenty billion, three hundred forty million, three hundred forty-three thousand, three hundred twenty-one".