21001100012021 has 2 divisors, whose sum is σ = 21001100012022. Its totient is φ = 21001100012020.

The previous prime is 21001100011973. The next prime is 21001100012023. The reversal of 21001100012021 is 12021000110012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19221648062500 + 1779451949521 = 4384250^2 + 1333961^2 .

It is a cyclic number.

It is not a de Polignac number, because 21001100012021 - 2³⁸ = 20726222105077 is a prime.

Together with 21001100012023, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21001100011993 and 21001100012011.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21001100012023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500550006010 + 10500550006011.

It is an arithmetic number, because the mean of its divisors is an integer number (10500550006011).

Almost surely, 2^{21001100012021} is an apocalyptic number.

It is an amenable number.

21001100012021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001100012021 is an equidigital number, since it uses as much as digits as its factorization.

21001100012021 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 21001100012021 its reverse (12021000110012), we get a palindrome (33022100122033).

The spelling of 21001100012021 in words is "twenty-one trillion, one billion, one hundred million, twelve thousand, twenty-one".