21230013221 has 4 divisors (see below), whose sum is σ = 21278373600. Its totient is φ = 21181652844.

The previous prime is 21230013197. The next prime is 21230013263. The reversal of 21230013221 is 12231003212.

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 21230013221 - 2⁶ = 21230013157 is a prime.

It is a super-2 number, since 2×21230013221² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21230013221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21230013281) 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, 24179531 + ... + 24180408.

It is an arithmetic number, because the mean of its divisors is an integer number (5319593400).

Almost surely, 2^21230013221 is an apocalyptic number.

It is an amenable number.

21230013221 is a deficient number, since it is larger than the sum of its proper divisors (48360379).

21230013221 is an equidigital number, since it uses as much as digits as its factorization.

21230013221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48360378.

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 21230013221 its reverse (12231003212), we get a palindrome (33461016433).

The spelling of 21230013221 in words is "twenty-one billion, two hundred thirty million, thirteen thousand, two hundred twenty-one".