21021223111 has 4 divisors (see below), whose sum is σ = 24024254992. Its totient is φ = 18018191232.

The previous prime is 21021223087. The next prime is 21021223123. The reversal of 21021223111 is 11132212012.

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 21021223111 - 2²³ = 21012834503 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021223151) 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, 1501515930 + ... + 1501515943.

It is an arithmetic number, because the mean of its divisors is an integer number (6006063748).

Almost surely, 2^21021223111 is an apocalyptic number.

21021223111 is a deficient number, since it is larger than the sum of its proper divisors (3003031881).

21021223111 is an equidigital number, since it uses as much as digits as its factorization.

21021223111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3003031880.

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

Adding to 21021223111 its reverse (11132212012), we get a palindrome (32153435123).

The spelling of 21021223111 in words is "twenty-one billion, twenty-one million, two hundred twenty-three thousand, one hundred eleven".