21571267 has 2 divisors, whose sum is σ = 21571268. Its totient is φ = 21571266.

The previous prime is 21571243. The next prime is 21571279. The reversal of 21571267 is 76217512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21571267 - 2⁷ = 21571139 is a prime.

It is a Chen prime.

It is equal to p_1363783 and since 21571267 and 1363783 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21571237) 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, 10785633 + 10785634.

It is an arithmetic number, because the mean of its divisors is an integer number (10785634).

Almost surely, 2^21571267 is an apocalyptic number.

21571267 is a deficient number, since it is larger than the sum of its proper divisors (1).

21571267 is an equidigital number, since it uses as much as digits as its factorization.

21571267 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5880, while the sum is 31.

The square root of 21571267 is about 4644.4878081442. The cubic root of 21571267 is about 278.3717874687.

Adding to 21571267 its reverse (76217512), we get a palindrome (97788779).

The spelling of 21571267 in words is "twenty-one million, five hundred seventy-one thousand, two hundred sixty-seven".