1641666647 has 2 divisors, whose sum is σ = 1641666648. Its totient is φ = 1641666646.

The previous prime is 1641666617. The next prime is 1641666707. The reversal of 1641666647 is 7466661461.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1641666647 - 2⁸ = 1641666391 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1641666617) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 820833323 + 820833324.

It is an arithmetic number, because the mean of its divisors is an integer number (820833324).

Almost surely, 2^1641666647 is an apocalyptic number.

1641666647 is a deficient number, since it is larger than the sum of its proper divisors (1).

1641666647 is an equidigital number, since it uses as much as digits as its factorization.

1641666647 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 870912, while the sum is 47.

The square root of 1641666647 is about 40517.4856944505. The cubic root of 1641666647 is about 1179.6730509969.

The spelling of 1641666647 in words is "one billion, six hundred forty-one million, six hundred sixty-six thousand, six hundred forty-seven".