21212110101 has 32 divisors (see below), whose sum is σ = 35750434048. Its totient is φ = 10886400000.

The previous prime is 21212110097. The next prime is 21212110109. The reversal of 21212110101 is 10101121212.

It is not a de Polignac number, because 21212110101 - 2² = 21212110097 is a prime.

It is a super-3 number, since 3×21212110101³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212110109) 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 31 ways as a sum of consecutive naturals, for example, 1039900 + ... + 1060101.

It is an arithmetic number, because the mean of its divisors is an integer number (1117201064).

Almost surely, 2^21212110101 is an apocalyptic number.

21212110101 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21212110101 is a deficient number, since it is larger than the sum of its proper divisors (14538323947).

21212110101 is a wasteful number, since it uses less digits than its factorization.

21212110101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2100061.

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

Adding to 21212110101 its reverse (10101121212), we get a palindrome (31313231313).

It can be divided in two parts, 212121 and 10101, that added together give a palindrome (222222).

The spelling of 21212110101 in words is "twenty-one billion, two hundred twelve million, one hundred ten thousand, one hundred one".