21021051343421 has 4 divisors (see below), whose sum is σ = 21021982861152. Its totient is φ = 21020119825692.

The previous prime is 21021051343399. The next prime is 21021051343429. The reversal of 21021051343421 is 12434315012012.

It is a happy number.

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 a cyclic number.

It is not a de Polignac number, because 21021051343421 - 2³⁴ = 21003871474237 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 (21021051343429) 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, 465725015 + ... + 465770148.

It is an arithmetic number, because the mean of its divisors is an integer number (5255495715288).

Almost surely, 2^{21021051343421} is an apocalyptic number.

It is an amenable number.

21021051343421 is a deficient number, since it is larger than the sum of its proper divisors (931517731).

21021051343421 is an equidigital number, since it uses as much as digits as its factorization.

21021051343421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 931517730.

The product of its (nonzero) digits is 5760, while the sum is 29.

Adding to 21021051343421 its reverse (12434315012012), we get a palindrome (33455366355433).

The spelling of 21021051343421 in words is "twenty-one trillion, twenty-one billion, fifty-one million, three hundred forty-three thousand, four hundred twenty-one".