21317267 has 2 divisors, whose sum is σ = 21317268. Its totient is φ = 21317266.

The previous prime is 21317249. The next prime is 21317327. The reversal of 21317267 is 76271312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21317267 - 2¹⁶ = 21251731 is a prime.

It is not a weakly prime, because it can be changed into another prime (21347267) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10658633 + 10658634.

It is an arithmetic number, because the mean of its divisors is an integer number (10658634).

Almost surely, 2^21317267 is an apocalyptic number.

21317267 is a deficient number, since it is larger than the sum of its proper divisors (1).

21317267 is an equidigital number, since it uses as much as digits as its factorization.

21317267 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3528, while the sum is 29.

The square root of 21317267 is about 4617.0625943342. The cubic root of 21317267 is about 277.2748686714.

Adding to 21317267 its reverse (76271312), we get a palindrome (97588579).

The spelling of 21317267 in words is "twenty-one million, three hundred seventeen thousand, two hundred sixty-seven".