21243002221 has 8 divisors (see below), whose sum is σ = 24426661184. Its totient is φ = 18096579360.

The previous prime is 21243002219. The next prime is 21243002257. The reversal of 21243002221 is 12220034212.

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 21243002221 - 2¹ = 21243002219 is a prime.

It is a super-2 number, since 2×21243002221² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21243005221) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9307800 + ... + 9310081.

It is an arithmetic number, because the mean of its divisors is an integer number (3053332648).

Almost surely, 2^21243002221 is an apocalyptic number.

It is an amenable number.

21243002221 is a deficient number, since it is larger than the sum of its proper divisors (3183658963).

21243002221 is a wasteful number, since it uses less digits than its factorization.

21243002221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18618051.

The product of its (nonzero) digits is 384, while the sum is 19.

Adding to 21243002221 its reverse (12220034212), we get a palindrome (33463036433).

The spelling of 21243002221 in words is "twenty-one billion, two hundred forty-three million, two thousand, two hundred twenty-one".