21166147 has 2 divisors, whose sum is σ = 21166148. Its totient is φ = 21166146.

The previous prime is 21166129. The next prime is 21166151. The reversal of 21166147 is 74166112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21166147 is a prime.

It is not a weakly prime, because it can be changed into another prime (21166157) by changing a digit.

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

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10583073 + 10583074.

It is an arithmetic number, because the mean of its divisors is an integer number (10583074).

Almost surely, 2^21166147 is an apocalyptic number.

21166147 is a deficient number, since it is larger than the sum of its proper divisors (1).

21166147 is an equidigital number, since it uses as much as digits as its factorization.

21166147 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2016, while the sum is 28.

The square root of 21166147 is about 4600.6681036563. The cubic root of 21166147 is about 276.6181055396.

The spelling of 21166147 in words is "twenty-one million, one hundred sixty-six thousand, one hundred forty-seven".