21212011321 has 4 divisors (see below), whose sum is σ = 21307132672. Its totient is φ = 21116889972.

The previous prime is 21212011309. The next prime is 21212011339. The reversal of 21212011321 is 12311021212.

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 21212011321 - 2¹³ = 21212003129 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21212011295 and 21212011304.

It is not an unprimeable number, because it can be changed into a prime (21212011021) 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, 47560341 + ... + 47560786.

It is an arithmetic number, because the mean of its divisors is an integer number (5326783168).

Almost surely, 2^21212011321 is an apocalyptic number.

It is an amenable number.

21212011321 is a deficient number, since it is larger than the sum of its proper divisors (95121351).

21212011321 is an equidigital number, since it uses as much as digits as its factorization.

21212011321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95121350.

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 21212011321 its reverse (12311021212), we get a palindrome (33523032533).

The spelling of 21212011321 in words is "twenty-one billion, two hundred twelve million, eleven thousand, three hundred twenty-one".