21212021101 has 4 divisors (see below), whose sum is σ = 22134282912. Its totient is φ = 20289759292.

The previous prime is 21212021071. The next prime is 21212021123. The reversal of 21212021101 is 10112021212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21212021101 - 2¹¹ = 21212019053 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 (21212021161) 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 3 ways as a sum of consecutive naturals, for example, 461130871 + ... + 461130916.

It is an arithmetic number, because the mean of its divisors is an integer number (5533570728).

Almost surely, 2^21212021101 is an apocalyptic number.

It is an amenable number.

21212021101 is a deficient number, since it is larger than the sum of its proper divisors (922261811).

21212021101 is an equidigital number, since it uses as much as digits as its factorization.

21212021101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 922261810.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21212021101 its reverse (10112021212), we get a palindrome (31324042313).

The spelling of 21212021101 in words is "twenty-one billion, two hundred twelve million, twenty-one thousand, one hundred one".