21101000021021 has 2 divisors, whose sum is σ = 21101000021022. Its totient is φ = 21101000021020.

The previous prime is 21101000021009. The next prime is 21101000021051. The reversal of 21101000021021 is 12012000010112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20531864064100 + 569135956921 = 4531210^2 + 754411^2 .

It is a cyclic number.

It is not a de Polignac number, because 21101000021021 - 2³⁴ = 21083820151837 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21101000020993 and 21101000021011.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21101000021051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550500010510 + 10550500010511.

It is an arithmetic number, because the mean of its divisors is an integer number (10550500010511).

Almost surely, 2^{21101000021021} is an apocalyptic number.

It is an amenable number.

21101000021021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101000021021 is an equidigital number, since it uses as much as digits as its factorization.

21101000021021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21101000021021 its reverse (12012000010112), we get a palindrome (33113000031133).

The spelling of 21101000021021 in words is "twenty-one trillion, one hundred one billion, twenty-one thousand, twenty-one".