21420211321 has 4 divisors (see below), whose sum is σ = 21461168272. Its totient is φ = 21379254372.

The previous prime is 21420211313. The next prime is 21420211331. The reversal of 21420211321 is 12311202412.

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 21420211321 - 2³ = 21420211313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21420211301) 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 3 ways as a sum of consecutive naturals, for example, 20477691 + ... + 20478736.

It is an arithmetic number, because the mean of its divisors is an integer number (5365292068).

Almost surely, 2^21420211321 is an apocalyptic number.

It is an amenable number.

21420211321 is a deficient number, since it is larger than the sum of its proper divisors (40956951).

21420211321 is an equidigital number, since it uses as much as digits as its factorization.

21420211321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40956950.

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 21420211321 its reverse (12311202412), we get a palindrome (33731413733).

The spelling of 21420211321 in words is "twenty-one billion, four hundred twenty million, two hundred eleven thousand, three hundred twenty-one".