21120243101 has 4 divisors (see below), whose sum is σ = 21180074172. Its totient is φ = 21060412032.

The previous prime is 21120243091. The next prime is 21120243139. The reversal of 21120243101 is 10134202112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3144405625 + 17975837476 = 56075^2 + 134074^2 .

It is a cyclic number.

It is not a de Polignac number, because 21120243101 - 2¹⁴ = 21120226717 is a prime.

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 21120243101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120243901) 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, 29915006 + ... + 29915711.

It is an arithmetic number, because the mean of its divisors is an integer number (5295018543).

Almost surely, 2^21120243101 is an apocalyptic number.

It is an amenable number.

21120243101 is a deficient number, since it is larger than the sum of its proper divisors (59831071).

21120243101 is an equidigital number, since it uses as much as digits as its factorization.

21120243101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59831070.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 21120243101 its reverse (10134202112), we get a palindrome (31254445213).

The spelling of 21120243101 in words is "twenty-one billion, one hundred twenty million, two hundred forty-three thousand, one hundred one".