667 has 4 divisors (see below), whose sum is σ = 720. Its totient is φ = 616.

The previous prime is 661. The next prime is 673. The reversal of 667 is 766.

Adding to 667 its sum of digits (19), we get a palindrome (686).

Adding to 667 its product of digits (252), we get a palindrome (919).

Subtracting 667 from its reverse (766), we obtain a palindrome (99).

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 766 = 2 ⋅383.

It is an interprime number because it is at equal distance from previous prime (661) and next prime (673).

It is a cyclic number.

It is not a de Polignac number, because 667 - 2^{3} = 659 is a prime.

It is a magnanimous number.

It is a pancake number, because a pancake can be divided into 667 parts by 36 straight cuts.

It is a Duffinian number.

It is a plaindrome in base 8, base 10, base 11, base 12, base 14 and base 16.

It is a nialpdrome in base 9.

It is not an unprimeable number, because it can be changed into a prime (661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9 + ... + 37.

It is an arithmetic number, because the mean of its divisors is an integer number (180).

2^{667} is an apocalyptic number.

667 is a deficient number, since it is larger than the sum of its proper divisors (53).

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

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

The sum of its prime factors is 52.

The product of its digits is 252, while the sum is 19.

The square root of 667 is about 25.8263431403. The cubic root of 667 is about 8.7372603722.

The spelling of 667 in words is "six hundred sixty-seven", and thus it is an aban number and an oban number.

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