21102120101 has 2 divisors, whose sum is σ = 21102120102. Its totient is φ = 21102120100.

The previous prime is 21102120073. The next prime is 21102120107. The reversal of 21102120101 is 10102120112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20814987076 + 287133025 = 144274^2 + 16945^2 .

It is a cyclic number.

It is not a de Polignac number, because 21102120101 - 2²⁶ = 21035011237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21102120107) 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, 10551060050 + 10551060051.

It is an arithmetic number, because the mean of its divisors is an integer number (10551060051).

Almost surely, 2^21102120101 is an apocalyptic number.

It is an amenable number.

21102120101 is a deficient number, since it is larger than the sum of its proper divisors (1).

21102120101 is an equidigital number, since it uses as much as digits as its factorization.

21102120101 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 11.

Adding to 21102120101 its sum of digits (11), we get a palindrome (21102120112).

Adding to 21102120101 its reverse (10102120112), we get a palindrome (31204240213).

The spelling of 21102120101 in words is "twenty-one billion, one hundred two million, one hundred twenty thousand, one hundred one".