21212001011 has 4 divisors (see below), whose sum is σ = 21215704152. Its totient is φ = 21208297872.

The previous prime is 21212000987. The next prime is 21212001029. The reversal of 21212001011 is 11010021212.

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 21212001011 - 2²⁶ = 21144892147 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21212000983 and 21212001001.

It is not an unprimeable number, because it can be changed into a prime (21212001511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1842965 + ... + 1854438.

It is an arithmetic number, because the mean of its divisors is an integer number (5303926038).

Almost surely, 2^21212001011 is an apocalyptic number.

21212001011 is a deficient number, since it is larger than the sum of its proper divisors (3703141).

21212001011 is an equidigital number, since it uses as much as digits as its factorization.

21212001011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3703140.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21212001011 its reverse (11010021212), we get a palindrome (32222022223).

The spelling of 21212001011 in words is "twenty-one billion, two hundred twelve million, one thousand, eleven".