21135347 has 2 divisors, whose sum is σ = 21135348. Its totient is φ = 21135346.

The previous prime is 21135337. The next prime is 21135349. The reversal of 21135347 is 74353112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21135347 - 2¹² = 21131251 is a prime.

Together with 21135349, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21135349) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10567673 + 10567674.

It is an arithmetic number, because the mean of its divisors is an integer number (10567674).

Almost surely, 2^21135347 is an apocalyptic number.

21135347 is a deficient number, since it is larger than the sum of its proper divisors (1).

21135347 is an equidigital number, since it uses as much as digits as its factorization.

21135347 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2520, while the sum is 26.

The square root of 21135347 is about 4597.3195451263. The cubic root of 21135347 is about 276.4838664399.

Adding to 21135347 its reverse (74353112), we get a palindrome (95488459).

The spelling of 21135347 in words is "twenty-one million, one hundred thirty-five thousand, three hundred forty-seven".