21221111111 has 8 divisors (see below), whose sum is σ = 21438054000. Its totient is φ = 21004302400.

The previous prime is 21221111099. The next prime is 21221111113. The reversal of 21221111111 is 11111112212.

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

It is a cyclic number.

It is not a de Polignac number, because 21221111111 - 2¹⁸ = 21220848967 is a prime.

It is a super-3 number, since 3×21221111111³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

21221111111 is a modest number, since divided by 111111 gives 21221 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221111113) 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 7 ways as a sum of consecutive naturals, for example, 301355 + ... + 365043.

It is an arithmetic number, because the mean of its divisors is an integer number (2679756750).

Almost surely, 2^21221111111 is an apocalyptic number.

21221111111 is a deficient number, since it is larger than the sum of its proper divisors (216942889).

21221111111 is a wasteful number, since it uses less digits than its factorization.

21221111111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67089.

The product of its digits is 8, while the sum is 14.

Adding to 21221111111 its reverse (11111112212), we get a palindrome (32332223323).

It can be divided in two parts, 212211 and 11111, that added together give a palindrome (223322).

The spelling of 21221111111 in words is "twenty-one billion, two hundred twenty-one million, one hundred eleven thousand, one hundred eleven".