21111012101021 has 2 divisors, whose sum is σ = 21111012101022. Its totient is φ = 21111012101020.

The previous prime is 21111012100999. The next prime is 21111012101089. The reversal of 21111012101021 is 12010121011112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18233625907225 + 2877386193796 = 4270085^2 + 1696286^2 .

It is a cyclic number.

It is not a de Polignac number, because 21111012101021 - 2¹⁸ = 21111011838877 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21111012100987 and 21111012101005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21111012101321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555506050510 + 10555506050511.

It is an arithmetic number, because the mean of its divisors is an integer number (10555506050511).

Almost surely, 2^{21111012101021} is an apocalyptic number.

It is an amenable number.

21111012101021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111012101021 is an equidigital number, since it uses as much as digits as its factorization.

21111012101021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8, while the sum is 14.

Adding to 21111012101021 its reverse (12010121011112), we get a palindrome (33121133112133).

The spelling of 21111012101021 in words is "twenty-one trillion, one hundred eleven billion, twelve million, one hundred one thousand, twenty-one".