21257067 has 16 divisors (see below), whose sum is σ = 32130560. Its totient is φ = 12392352.

The previous prime is 21257059. The next prime is 21257077. The reversal of 21257067 is 76075212.

It is not a de Polignac number, because 21257067 - 2³ = 21257059 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21257017) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13603 + ... + 15084.

It is an arithmetic number, because the mean of its divisors is an integer number (2008160).

Almost surely, 2^21257067 is an apocalyptic number.

21257067 is a deficient number, since it is larger than the sum of its proper divisors (10873493).

21257067 is a wasteful number, since it uses less digits than its factorization.

21257067 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28722.

The product of its (nonzero) digits is 5880, while the sum is 30.

The square root of 21257067 is about 4610.5386887001. The cubic root of 21257067 is about 277.0136143482.

The spelling of 21257067 in words is "twenty-one million, two hundred fifty-seven thousand, sixty-seven".