21230424221 has 4 divisors (see below), whose sum is σ = 21231807072. Its totient is φ = 21229041372.

The previous prime is 21230424161. The next prime is 21230424223. The reversal of 21230424221 is 12242403212.

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 21230424221 - 2⁶ = 21230424157 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 (21230424223) 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, 668135 + ... + 699188.

It is an arithmetic number, because the mean of its divisors is an integer number (5307951768).

Almost surely, 2^21230424221 is an apocalyptic number.

It is an amenable number.

21230424221 is a deficient number, since it is larger than the sum of its proper divisors (1382851).

21230424221 is a wasteful number, since it uses less digits than its factorization.

21230424221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1382850.

The product of its (nonzero) digits is 1536, while the sum is 23.

Adding to 21230424221 its reverse (12242403212), we get a palindrome (33472827433).

The spelling of 21230424221 in words is "twenty-one billion, two hundred thirty million, four hundred twenty-four thousand, two hundred twenty-one".