666999663 has 8 divisors (see below), whose sum is σ = 970181376. Its totient is φ = 404242200.

The previous prime is 666999659. The next prime is 666999677. The reversal of 666999663 is 366999666.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 666999663 - 2² = 666999659 is a prime.

It is a super-2 number, since 2×666999663² = 889777100884227138, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 666999597 and 666999606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666999863) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10106023 + ... + 10106088.

It is an arithmetic number, because the mean of its divisors is an integer number (121272672).

Almost surely, 2^666999663 is an apocalyptic number.

666999663 is a deficient number, since it is larger than the sum of its proper divisors (303181713).

666999663 is a wasteful number, since it uses less digits than its factorization.

666999663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20212125.

The product of its digits is 17006112, while the sum is 60.

The square root of 666999663 is about 25826.3366159430. The cubic root of 666999663 is about 873.7258900717.

The spelling of 666999663 in words is "six hundred sixty-six million, nine hundred ninety-nine thousand, six hundred sixty-three".