21102101 has 2 divisors, whose sum is σ = 21102102. Its totient is φ = 21102100.

The previous prime is 21102091. The next prime is 21102113. The reversal of 21102101 is 10120112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20921476 + 180625 = 4574^2 + 425^2 .

It is a cyclic number.

It is not a de Polignac number, because 21102101 - 2¹⁴ = 21085717 is a prime.

It is a super-2 number, since 2×21102101² = 890597333228402, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21102161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551050 + 10551051.

It is an arithmetic number, because the mean of its divisors is an integer number (10551051).

Almost surely, 2^21102101 is an apocalyptic number.

It is an amenable number.

21102101 is a deficient number, since it is larger than the sum of its proper divisors (1).

21102101 is an equidigital number, since it uses as much as digits as its factorization.

21102101 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4, while the sum is 8.

The square root of 21102101 is about 4593.7023194804. The cubic root of 21102101 is about 276.3388202208.

Adding to 21102101 its reverse (10120112), we get a palindrome (31222213).

The spelling of 21102101 in words is "twenty-one million, one hundred two thousand, one hundred one".