21010110109 has 2 divisors, whose sum is σ = 21010110110. Its totient is φ = 21010110108.

The previous prime is 21010110101. The next prime is 21010110113. The reversal of 21010110109 is 90101101012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17558900100 + 3451210009 = 132510^2 + 58747^2 .

It is a cyclic number.

It is not a de Polignac number, because 21010110109 - 2³ = 21010110101 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21010110092 and 21010110101.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21010110101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505055054 + 10505055055.

It is an arithmetic number, because the mean of its divisors is an integer number (10505055055).

Almost surely, 2^21010110109 is an apocalyptic number.

It is an amenable number.

21010110109 is a deficient number, since it is larger than the sum of its proper divisors (1).

21010110109 is an equidigital number, since it uses as much as digits as its factorization.

21010110109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18, while the sum is 16.

The spelling of 21010110109 in words is "twenty-one billion, ten million, one hundred ten thousand, one hundred nine".