21102071 has 2 divisors, whose sum is σ = 21102072. Its totient is φ = 21102070.

The previous prime is 21102047. The next prime is 21102079. The reversal of 21102071 is 17020112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21102071 - 2¹⁸ = 20839927 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21102079) 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, 10551035 + 10551036.

It is an arithmetic number, because the mean of its divisors is an integer number (10551036).

Almost surely, 2^21102071 is an apocalyptic number.

21102071 is a deficient number, since it is larger than the sum of its proper divisors (1).

21102071 is an equidigital number, since it uses as much as digits as its factorization.

21102071 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28, while the sum is 14.

The square root of 21102071 is about 4593.6990541393. The cubic root of 21102071 is about 276.3386892675.

Adding to 21102071 its reverse (17020112), we get a palindrome (38122183).

The spelling of 21102071 in words is "twenty-one million, one hundred two thousand, seventy-one".