663989947 has 2 divisors, whose sum is σ = 663989948. Its totient is φ = 663989946.

The previous prime is 663989933. The next prime is 663989983. The reversal of 663989947 is 749989366.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 663989947 - 2¹⁵ = 663957179 is a prime.

It is not a weakly prime, because it can be changed into another prime (663989747) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 331994973 + 331994974.

It is an arithmetic number, because the mean of its divisors is an integer number (331994974).

Almost surely, 2^663989947 is an apocalyptic number.

663989947 is a deficient number, since it is larger than the sum of its proper divisors (1).

663989947 is an equidigital number, since it uses as much as digits as its factorization.

663989947 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17635968, while the sum is 61.

The square root of 663989947 is about 25768.0023866810. The cubic root of 663989947 is about 872.4097314679.

The spelling of 663989947 in words is "six hundred sixty-three million, nine hundred eighty-nine thousand, nine hundred forty-seven".