21112300021 has 4 divisors (see below), whose sum is σ = 21115921600. Its totient is φ = 21108678444.

The previous prime is 21112300007. The next prime is 21112300039. The reversal of 21112300021 is 12000321112.

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 21112300021 - 2³¹ = 18964816373 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21112299974 and 21112300010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112300081) 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, 1802031 + ... + 1813708.

It is an arithmetic number, because the mean of its divisors is an integer number (5278980400).

Almost surely, 2^21112300021 is an apocalyptic number.

It is an amenable number.

21112300021 is a deficient number, since it is larger than the sum of its proper divisors (3621579).

21112300021 is an equidigital number, since it uses as much as digits as its factorization.

21112300021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3621578.

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 21112300021 its reverse (12000321112), we get a palindrome (33112621133).

The spelling of 21112300021 in words is "twenty-one billion, one hundred twelve million, three hundred thousand, twenty-one".