21001012021061 has 2 divisors, whose sum is σ = 21001012021062. Its totient is φ = 21001012021060.

The previous prime is 21001012021013. The next prime is 21001012021063. The reversal of 21001012021061 is 16012021010012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20229260313025 + 771751708036 = 4497695^2 + 878494^2 .

It is a cyclic number.

It is not a de Polignac number, because 21001012021061 - 2¹⁴ = 21001012004677 is a prime.

Together with 21001012021063, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21001012021063) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500506010530 + 10500506010531.

It is an arithmetic number, because the mean of its divisors is an integer number (10500506010531).

Almost surely, 2^{21001012021061} is an apocalyptic number.

It is an amenable number.

21001012021061 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001012021061 is an equidigital number, since it uses as much as digits as its factorization.

21001012021061 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48, while the sum is 17.

Adding to 21001012021061 its reverse (16012021010012), we get a palindrome (37013033031073).

The spelling of 21001012021061 in words is "twenty-one trillion, one billion, twelve million, twenty-one thousand, sixty-one".