21200111010021 has 4 divisors (see below), whose sum is σ = 28266814680032. Its totient is φ = 14133407340012.

The previous prime is 21200111009969. The next prime is 21200111010047. The reversal of 21200111010021 is 12001011100212.

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 not a de Polignac number, because 21200111010021 - 2⁹ = 21200111009509 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21200111009979 and 21200111010006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21200111011021) 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, 3533351835001 + ... + 3533351835006.

It is an arithmetic number, because the mean of its divisors is an integer number (7066703670008).

Almost surely, 2^{21200111010021} is an apocalyptic number.

It is an amenable number.

21200111010021 is a deficient number, since it is larger than the sum of its proper divisors (7066703670011).

21200111010021 is an equidigital number, since it uses as much as digits as its factorization.

21200111010021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7066703670010.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21200111010021 its reverse (12001011100212), we get a palindrome (33201122110233).

The spelling of 21200111010021 in words is "twenty-one trillion, two hundred billion, one hundred eleven million, ten thousand, twenty-one".