21121212021101 has 4 divisors (see below), whose sum is σ = 21123650124192. Its totient is φ = 21118773918012.

The previous prime is 21121212021097. The next prime is 21121212021109. The reversal of 21121212021101 is 10112021212112.

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 21121212021101 - 2² = 21121212021097 is a prime.

It is a super-2 number, since 2×21121212021101² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21121212021101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121212021109) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1219038551 + ... + 1219055876.

It is an arithmetic number, because the mean of its divisors is an integer number (5280912531048).

Almost surely, 2^{21121212021101} is an apocalyptic number.

It is an amenable number.

21121212021101 is a deficient number, since it is larger than the sum of its proper divisors (2438103091).

21121212021101 is an equidigital number, since it uses as much as digits as its factorization.

21121212021101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2438103090.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21121212021101 its reverse (10112021212112), we get a palindrome (31233233233213).

The spelling of 21121212021101 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred twelve million, twenty-one thousand, one hundred one".