21212421213 has 8 divisors (see below), whose sum is σ = 28286375776. Its totient is φ = 14140040400.

The previous prime is 21212421187. The next prime is 21212421257. The reversal of 21212421213 is 31212421212.

It is a happy number.

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

It is not a de Polignac number, because 21212421213 - 2²² = 21208226909 is a prime.

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 21212421213.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212420213) 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, 361618 + ... + 416163.

It is an arithmetic number, because the mean of its divisors is an integer number (3535796972).

Almost surely, 2^21212421213 is an apocalyptic number.

It is an amenable number.

21212421213 is a deficient number, since it is larger than the sum of its proper divisors (7073954563).

21212421213 is an equidigital number, since it uses as much as digits as its factorization.

21212421213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 786875.

The product of its digits is 384, while the sum is 21.

Adding to 21212421213 its reverse (31212421212), we get a palindrome (52424842425).

Subtracting 21212421213 from its reverse (31212421212), we obtain a palindrome (9999999999).

The spelling of 21212421213 in words is "twenty-one billion, two hundred twelve million, four hundred twenty-one thousand, two hundred thirteen".