21064443401 has 4 divisors (see below), whose sum is σ = 21156428100. Its totient is φ = 20972458704.

The previous prime is 21064443391. The next prime is 21064443403. The reversal of 21064443401 is 10434446012.

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 16531787776 + 4532655625 = 128576^2 + 67325^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21064443401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21064443403) 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, 45992006 + ... + 45992463.

It is an arithmetic number, because the mean of its divisors is an integer number (5289107025).

Almost surely, 2^21064443401 is an apocalyptic number.

It is an amenable number.

21064443401 is a deficient number, since it is larger than the sum of its proper divisors (91984699).

21064443401 is an equidigital number, since it uses as much as digits as its factorization.

21064443401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91984698.

The product of its (nonzero) digits is 9216, while the sum is 29.

Adding to 21064443401 its reverse (10434446012), we get a palindrome (31498889413).

The spelling of 21064443401 in words is "twenty-one billion, sixty-four million, four hundred forty-three thousand, four hundred one".