21320267 has 2 divisors, whose sum is σ = 21320268. Its totient is φ = 21320266.

The previous prime is 21320239. The next prime is 21320297. The reversal of 21320267 is 76202312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21320267 - 2⁶ = 21320203 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21320297) 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, 10660133 + 10660134.

It is an arithmetic number, because the mean of its divisors is an integer number (10660134).

Almost surely, 2^21320267 is an apocalyptic number.

21320267 is a deficient number, since it is larger than the sum of its proper divisors (1).

21320267 is an equidigital number, since it uses as much as digits as its factorization.

21320267 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 23.

The square root of 21320267 is about 4617.3874647900. The cubic root of 21320267 is about 277.2878751165.

Adding to 21320267 its reverse (76202312), we get a palindrome (97522579).

The spelling of 21320267 in words is "twenty-one million, three hundred twenty thousand, two hundred sixty-seven".