21135071 has 2 divisors, whose sum is σ = 21135072. Its totient is φ = 21135070.

The previous prime is 21135053. The next prime is 21135073. The reversal of 21135071 is 17053112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21135071 - 2¹⁸ = 20872927 is a prime.

Together with 21135073, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21135073) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10567535 + 10567536.

It is an arithmetic number, because the mean of its divisors is an integer number (10567536).

Almost surely, 2^21135071 is an apocalyptic number.

21135071 is a deficient number, since it is larger than the sum of its proper divisors (1).

21135071 is an equidigital number, since it uses as much as digits as its factorization.

21135071 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 210, while the sum is 20.

The square root of 21135071 is about 4597.2895275369. The cubic root of 21135071 is about 276.4826629287.

Adding to 21135071 its reverse (17053112), we get a palindrome (38188183).

The spelling of 21135071 in words is "twenty-one million, one hundred thirty-five thousand, seventy-one".