667647 has 12 divisors (see below), whose sum is σ = 995904. Its totient is φ = 430560.

The previous prime is 667643. The next prime is 667649. The reversal of 667647 is 746766.

667647 is a `hidden beast` number, since 6 + 6 + 7 + 647 = 666.

It is not a de Polignac number, because 667647 - 2² = 667643 is a prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 667647.

It is not an unprimeable number, because it can be changed into a prime (667643) 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, 918 + ... + 1475.

It is an arithmetic number, because the mean of its divisors is an integer number (82992).

2⁶⁶⁷⁶⁴⁷ is an apocalyptic number.

667647 is a deficient number, since it is larger than the sum of its proper divisors (328257).

667647 is a wasteful number, since it uses less digits than its factorization.

667647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2430 (or 2427 counting only the distinct ones).

The product of its digits is 42336, while the sum is 36.

The square root of 667647 is about 817.0966895050. The cubic root of 667647 is about 87.4008455043.

The spelling of 667647 in words is "six hundred sixty-seven thousand, six hundred forty-seven".