665947 has 2 divisors, whose sum is σ = 665948. Its totient is φ = 665946.

The previous prime is 665923. The next prime is 665953. The reversal of 665947 is 749566.

665947 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665947 is a prime.

It is a plaindrome in base 14.

It is not a weakly prime, because it can be changed into another prime (665047) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332973 + 332974.

It is an arithmetic number, because the mean of its divisors is an integer number (332974).

2⁶⁶⁵⁹⁴⁷ is an apocalyptic number.

665947 is a deficient number, since it is larger than the sum of its proper divisors (1).

665947 is an equidigital number, since it uses as much as digits as its factorization.

665947 is an evil number, because the sum of its binary digits is even.

The product of its digits is 45360, while the sum is 37.

The square root of 665947 is about 816.0557578989. The cubic root of 665947 is about 87.3266008187.

The spelling of 665947 in words is "six hundred sixty-five thousand, nine hundred forty-seven".