663440671 has 2 divisors, whose sum is σ = 663440672. Its totient is φ = 663440670.

The previous prime is 663440669. The next prime is 663440677. The reversal of 663440671 is 176044366.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 663440671 - 2¹ = 663440669 is a prime.

Together with 663440669, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 663440671.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (663440677) 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, 331720335 + 331720336.

It is an arithmetic number, because the mean of its divisors is an integer number (331720336).

Almost surely, 2^663440671 is an apocalyptic number.

663440671 is a deficient number, since it is larger than the sum of its proper divisors (1).

663440671 is an equidigital number, since it uses as much as digits as its factorization.

663440671 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72576, while the sum is 37.

The square root of 663440671 is about 25757.3420794926. The cubic root of 663440671 is about 872.1691023610.

The spelling of 663440671 in words is "six hundred sixty-three million, four hundred forty thousand, six hundred seventy-one".