21021210111 has 32 divisors (see below), whose sum is σ = 32023756800. Its totient is φ = 12141122400.

The previous prime is 21021210109. The next prime is 21021210121. The reversal of 21021210111 is 11101212012.

It is not a de Polignac number, because 21021210111 - 2¹ = 21021210109 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021210121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 154590 + ... + 256788.

It is an arithmetic number, because the mean of its divisors is an integer number (1000742400).

Almost surely, 2^21021210111 is an apocalyptic number.

21021210111 is a deficient number, since it is larger than the sum of its proper divisors (11002546689).

21021210111 is a wasteful number, since it uses less digits than its factorization.

21021210111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102507.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21021210111 its reverse (11101212012), we get a palindrome (32122422123).

It can be divided in two parts, 21021 and 210111, that added together give a palindrome (231132).

The spelling of 21021210111 in words is "twenty-one billion, twenty-one million, two hundred ten thousand, one hundred eleven".