663661111 has 4 divisors (see below), whose sum is σ = 671657112. Its totient is φ = 655665112.

The previous prime is 663661109. The next prime is 663661121. The reversal of 663661111 is 111166366.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 663661111 - 2¹ = 663661109 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (663661121) 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 in 3 ways as a sum of consecutive naturals, for example, 3997876 + ... + 3998041.

It is an arithmetic number, because the mean of its divisors is an integer number (167914278).

Almost surely, 2^663661111 is an apocalyptic number.

663661111 is a deficient number, since it is larger than the sum of its proper divisors (7996001).

663661111 is an equidigital number, since it uses as much as digits as its factorization.

663661111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7996000.

The product of its digits is 3888, while the sum is 31.

The square root of 663661111 is about 25761.6208923274. The cubic root of 663661111 is about 872.2656895793.

The spelling of 663661111 in words is "six hundred sixty-three million, six hundred sixty-one thousand, one hundred eleven".