21212122101 has 24 divisors (see below), whose sum is σ = 29914376544. Its totient is φ = 13368123360.

The previous prime is 21212122081. The next prime is 21212122187. The reversal of 21212122101 is 10122121212.

It is not a de Polignac number, because 21212122101 - 2¹⁷ = 21211991029 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212122201) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 484791 + ... + 526731.

It is an arithmetic number, because the mean of its divisors is an integer number (1246432356).

Almost surely, 2^21212122101 is an apocalyptic number.

It is an amenable number.

21212122101 is a deficient number, since it is larger than the sum of its proper divisors (8702254443).

21212122101 is a wasteful number, since it uses less digits than its factorization.

21212122101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42449 (or 42430 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21212122101 its reverse (10122121212), we get a palindrome (31334243313).

The spelling of 21212122101 in words is "twenty-one billion, two hundred twelve million, one hundred twenty-two thousand, one hundred one".