666646047 has 12 divisors (see below), whose sum is σ = 977306200. Its totient is φ = 437797008.

The previous prime is 666646033. The next prime is 666646069. The reversal of 666646047 is 740646666.

It is not a de Polignac number, because 666646047 - 2⁷ = 666645919 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 666645993 and 666646011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666646087) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 552172 + ... + 553377.

Almost surely, 2^666646047 is an apocalyptic number.

666646047 is a gapful number since it is divisible by the number (67) formed by its first and last digit.

666646047 is a deficient number, since it is larger than the sum of its proper divisors (310660153).

666646047 is a wasteful number, since it uses less digits than its factorization.

666646047 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1105622 (or 1105619 counting only the distinct ones).

The product of its (nonzero) digits is 870912, while the sum is 45.

The square root of 666646047 is about 25819.4896735005. The cubic root of 666646047 is about 873.5714581744.

The spelling of 666646047 in words is "six hundred sixty-six million, six hundred forty-six thousand, forty-seven".