21000211021021 has 4 divisors (see below), whose sum is σ = 21041960944032. Its totient is φ = 20958461098012.

The previous prime is 21000211021007. The next prime is 21000211021037. The reversal of 21000211021021 is 12012011200012.

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 a de Polignac number, because none of the positive numbers 2^k-21000211021021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21000211020992 and 21000211021010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000211021051) 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, 20874960751 + ... + 20874961756.

It is an arithmetic number, because the mean of its divisors is an integer number (5260490236008).

Almost surely, 2^{21000211021021} is an apocalyptic number.

It is an amenable number.

21000211021021 is a deficient number, since it is larger than the sum of its proper divisors (41749923011).

21000211021021 is an equidigital number, since it uses as much as digits as its factorization.

21000211021021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41749923010.

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

Adding to 21000211021021 its reverse (12012011200012), we get a palindrome (33012222221033).

The spelling of 21000211021021 in words is "twenty-one trillion, two hundred eleven million, twenty-one thousand, twenty-one".