21033032421 has 4 divisors (see below), whose sum is σ = 28044043232. Its totient is φ = 14022021612.

The previous prime is 21033032411. The next prime is 21033032441. The reversal of 21033032421 is 12423033012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21033032421 - 2¹¹ = 21033030373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21033032411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3505505401 + ... + 3505505406.

It is an arithmetic number, because the mean of its divisors is an integer number (7011010808).

Almost surely, 2^21033032421 is an apocalyptic number.

It is an amenable number.

21033032421 is a deficient number, since it is larger than the sum of its proper divisors (7011010811).

21033032421 is an equidigital number, since it uses as much as digits as its factorization.

21033032421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7011010810.

The product of its (nonzero) digits is 864, while the sum is 21.

Adding to 21033032421 its reverse (12423033012), we get a palindrome (33456065433).

The spelling of 21033032421 in words is "twenty-one billion, thirty-three million, thirty-two thousand, four hundred twenty-one".