666663995 has 16 divisors (see below), whose sum is σ = 809373600. Its totient is φ = 527116800.

The previous prime is 666663989. The next prime is 666664013. The reversal of 666663995 is 599366666.

It is a happy number.

It is not a de Polignac number, because 666663995 - 2⁴ = 666663979 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 666663995.

It is an unprimeable number.

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 in 15 ways as a sum of consecutive naturals, for example, 155075 + ... + 159315.

It is an arithmetic number, because the mean of its divisors is an integer number (50585850).

Almost surely, 2^666663995 is an apocalyptic number.

666663995 is a deficient number, since it is larger than the sum of its proper divisors (142709605).

666663995 is a wasteful number, since it uses less digits than its factorization.

666663995 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4606.

The product of its digits is 9447840, while the sum is 56.

The square root of 666663995 is about 25819.8372380617. The cubic root of 666663995 is about 873.5792977768.

The spelling of 666663995 in words is "six hundred sixty-six million, six hundred sixty-three thousand, nine hundred ninety-five".