21321011211 has 4 divisors (see below), whose sum is σ = 28428014952. Its totient is φ = 14214007472.

The previous prime is 21321011171. The next prime is 21321011233. The reversal of 21321011211 is 11211012312.

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 21321011211 - 2¹⁰ = 21321010187 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21321011251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3553501866 + ... + 3553501871.

It is an arithmetic number, because the mean of its divisors is an integer number (7107003738).

Almost surely, 2^21321011211 is an apocalyptic number.

21321011211 is a deficient number, since it is larger than the sum of its proper divisors (7107003741).

21321011211 is an equidigital number, since it uses as much as digits as its factorization.

21321011211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7107003740.

The product of its (nonzero) digits is 24, while the sum is 15.

Adding to 21321011211 its reverse (11211012312), we get a palindrome (32532023523).

It can be divided in two parts, 2132101 and 1211, that added together give a palindrome (2133312).

The spelling of 21321011211 in words is "twenty-one billion, three hundred twenty-one million, eleven thousand, two hundred eleven".