39947 has 4 divisors (see below), whose sum is σ = 40920. Its totient is φ = 38976.

The previous prime is 39937. The next prime is 39953. The reversal of 39947 is 74993.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74993 = 19 ⋅3947.

It is a cyclic number.

It is not a de Polignac number, because 39947 - 2⁶ = 39883 is a prime.

It is a Duffinian number.

Its product of digits (6804) is a multiple of the sum of its prime divisors (972).

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 39947.

It is not an unprimeable number, because it can be changed into a prime (39937) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 422 + ... + 507.

It is an arithmetic number, because the mean of its divisors is an integer number (10230).

2³⁹⁹⁴⁷ is an apocalyptic number.

39947 is a deficient number, since it is larger than the sum of its proper divisors (973).

39947 is an equidigital number, since it uses as much as digits as its factorization.

39947 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 972.

The product of its digits is 6804, while the sum is 32.

The square root of 39947 is about 199.8674560803. The cubic root of 39947 is about 34.1844074698.

The spelling of 39947 in words is "thirty-nine thousand, nine hundred forty-seven".