21011071 has 2 divisors, whose sum is σ = 21011072. Its totient is φ = 21011070.

The previous prime is 21011063. The next prime is 21011083. The reversal of 21011071 is 17011012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21011071 - 2³ = 21011063 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21017071) 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, 10505535 + 10505536.

It is an arithmetic number, because the mean of its divisors is an integer number (10505536).

Almost surely, 2^21011071 is an apocalyptic number.

21011071 is a deficient number, since it is larger than the sum of its proper divisors (1).

21011071 is an equidigital number, since it uses as much as digits as its factorization.

21011071 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14, while the sum is 13.

The square root of 21011071 is about 4583.7834809249. The cubic root of 21011071 is about 275.9408917391.

Adding to 21011071 its reverse (17011012), we get a palindrome (38022083).

The spelling of 21011071 in words is "twenty-one million, eleven thousand, seventy-one".