21335330421 has 20 divisors (see below), whose sum is σ = 32970309900. Its totient is φ = 13733084736.

The previous prime is 21335330411. The next prime is 21335330437. The reversal of 21335330421 is 12403353312.

21335330421 is a `hidden beast` number, since 2 + 1 + 3 + 353 + 304 + 2 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 4896500625 + 16438829796 = 69975^2 + 128214^2 .

It is not a de Polignac number, because 21335330421 - 2¹¹ = 21335328373 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21335330411) 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 19 ways as a sum of consecutive naturals, for example, 4539016 + ... + 4543713.

It is an arithmetic number, because the mean of its divisors is an integer number (1648515495).

Almost surely, 2^21335330421 is an apocalyptic number.

It is an amenable number.

21335330421 is a deficient number, since it is larger than the sum of its proper divisors (11634979479).

21335330421 is an equidigital number, since it uses as much as digits as its factorization.

21335330421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9082770 (or 9082761 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 27.

Adding to 21335330421 its reverse (12403353312), we get a palindrome (33738683733).

The spelling of 21335330421 in words is "twenty-one billion, three hundred thirty-five million, three hundred thirty thousand, four hundred twenty-one".