21035443321 has 4 divisors (see below), whose sum is σ = 21432338532. Its totient is φ = 20638548112.

The previous prime is 21035443307. The next prime is 21035443379. The reversal of 21035443321 is 12334453012.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15158534400 + 5876908921 = 123120^2 + 76661^2 .

It is a cyclic number.

It is not a de Polignac number, because 21035443321 - 2⁷ = 21035443193 is a prime.

It is a super-2 number, since 2×21035443321² (a number of 21 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 21035443321.

It is not an unprimeable number, because it can be changed into a prime (21035443721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 198447526 + ... + 198447631.

It is an arithmetic number, because the mean of its divisors is an integer number (5358084633).

Almost surely, 2^21035443321 is an apocalyptic number.

It is an amenable number.

21035443321 is a deficient number, since it is larger than the sum of its proper divisors (396895211).

21035443321 is an equidigital number, since it uses as much as digits as its factorization.

21035443321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 396895210.

The product of its (nonzero) digits is 8640, while the sum is 28.

Adding to 21035443321 its reverse (12334453012), we get a palindrome (33369896333).

The spelling of 21035443321 in words is "twenty-one billion, thirty-five million, four hundred forty-three thousand, three hundred twenty-one".