21343321421 has 4 divisors (see below), whose sum is σ = 21348873312. Its totient is φ = 21337769532.

The previous prime is 21343321399. The next prime is 21343321427. The reversal of 21343321421 is 12412334312.

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 21343321421 - 2²⁶ = 21276212557 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 (21343321427) 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, 2770175 + ... + 2777868.

It is an arithmetic number, because the mean of its divisors is an integer number (5337218328).

Almost surely, 2^21343321421 is an apocalyptic number.

It is an amenable number.

21343321421 is a deficient number, since it is larger than the sum of its proper divisors (5551891).

21343321421 is an equidigital number, since it uses as much as digits as its factorization.

21343321421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5551890.

The product of its digits is 3456, while the sum is 26.

Adding to 21343321421 its reverse (12412334312), we get a palindrome (33755655733).

The spelling of 21343321421 in words is "twenty-one billion, three hundred forty-three million, three hundred twenty-one thousand, four hundred twenty-one".