21001323421 has 8 divisors (see below), whose sum is σ = 22664033280. Its totient is φ = 19345359792.

The previous prime is 21001323403. The next prime is 21001323467. The reversal of 21001323421 is 12432310012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21001323421 - 2⁵ = 21001323389 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 (21001323481) 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 7 ways as a sum of consecutive naturals, for example, 1680085 + ... + 1692538.

It is an arithmetic number, because the mean of its divisors is an integer number (2833004160).

Almost surely, 2^21001323421 is an apocalyptic number.

It is an amenable number.

21001323421 is a deficient number, since it is larger than the sum of its proper divisors (1662709859).

21001323421 is a wasteful number, since it uses less digits than its factorization.

21001323421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3373115.

The product of its (nonzero) digits is 288, while the sum is 19.

Adding to 21001323421 its reverse (12432310012), we get a palindrome (33433633433).

The spelling of 21001323421 in words is "twenty-one billion, one million, three hundred twenty-three thousand, four hundred twenty-one".