21010110101 has 2 divisors, whose sum is σ = 21010110102. Its totient is φ = 21010110100.

The previous prime is 21010110067. The next prime is 21010110109. The reversal of 21010110101 is 10101101012.

It is a happy number.

It is an a-pointer prime, because the next prime (21010110109) can be obtained adding 21010110101 to its sum of digits (8).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15128754001 + 5881356100 = 122999^2 + 76690^2 .

It is a cyclic number.

It is not a de Polignac number, because 21010110101 - 2¹⁰ = 21010109077 is a prime.

It is a super-2 number, since 2×21010110101² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21010110109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505055050 + 10505055051.

It is an arithmetic number, because the mean of its divisors is an integer number (10505055051).

Almost surely, 2^21010110101 is an apocalyptic number.

It is an amenable number.

21010110101 is a deficient number, since it is larger than the sum of its proper divisors (1).

21010110101 is an equidigital number, since it uses as much as digits as its factorization.

21010110101 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2, while the sum is 8.

Adding to 21010110101 its reverse (10101101012), we get a palindrome (31111211113).

It can be divided in two parts, 2 and 1010110101, that multiplied together give a palindrome (2020220202).

The spelling of 21010110101 in words is "twenty-one billion, ten million, one hundred ten thousand, one hundred one".