663666559 has 2 divisors, whose sum is σ = 663666560. Its totient is φ = 663666558.

The previous prime is 663666551. The next prime is 663666571. The reversal of 663666559 is 955666366.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 663666559 - 2³ = 663666551 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (663666551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 331833279 + 331833280.

It is an arithmetic number, because the mean of its divisors is an integer number (331833280).

Almost surely, 2^663666559 is an apocalyptic number.

663666559 is a deficient number, since it is larger than the sum of its proper divisors (1).

663666559 is an equidigital number, since it uses as much as digits as its factorization.

663666559 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5248800, while the sum is 52.

The square root of 663666559 is about 25761.7266307986. The cubic root of 663666559 is about 872.2680763851.

It can be divided in two parts, 663666 and 559, that added together give a square (664225 = 815²).

The spelling of 663666559 in words is "six hundred sixty-three million, six hundred sixty-six thousand, five hundred fifty-nine".