21210310221 has 8 divisors (see below), whose sum is σ = 28284958464. Its totient is φ = 14137934400.

The previous prime is 21210310217. The next prime is 21210310229. The reversal of 21210310221 is 12201301212.

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

It is not a de Polignac number, because 21210310221 - 2² = 21210310217 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21210310221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210310229) 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, 546205 + ... + 583746.

It is an arithmetic number, because the mean of its divisors is an integer number (3535619808).

Almost surely, 2^21210310221 is an apocalyptic number.

It is an amenable number.

21210310221 is a deficient number, since it is larger than the sum of its proper divisors (7074648243).

21210310221 is a wasteful number, since it uses less digits than its factorization.

21210310221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1136211.

The product of its (nonzero) digits is 48, while the sum is 15.

Adding to 21210310221 its reverse (12201301212), we get a palindrome (33411611433).

Subtracting from 21210310221 its reverse (12201301212), we obtain a palindrome (9009009009).

The spelling of 21210310221 in words is "twenty-one billion, two hundred ten million, three hundred ten thousand, two hundred twenty-one".