21212002111 has 4 divisors (see below), whose sum is σ = 21221303824. Its totient is φ = 21202700400.

The previous prime is 21212002069. The next prime is 21212002139. The reversal of 21212002111 is 11120021212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21212002111 - 2¹³ = 21211993919 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21212002091 and 21212002100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212002711) 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, 4647435 + ... + 4651996.

It is an arithmetic number, because the mean of its divisors is an integer number (5305325956).

Almost surely, 2^21212002111 is an apocalyptic number.

21212002111 is a deficient number, since it is larger than the sum of its proper divisors (9301713).

21212002111 is an equidigital number, since it uses as much as digits as its factorization.

21212002111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9301712.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21212002111 its reverse (11120021212), we get a palindrome (32332023323).

The spelling of 21212002111 in words is "twenty-one billion, two hundred twelve million, two thousand, one hundred eleven".