39945 has 8 divisors (see below), whose sum is σ = 63936. Its totient is φ = 21296.

The previous prime is 39937. The next prime is 39953. The reversal of 39945 is 54993.

It is an interprime number because it is at equal distance from previous prime (39937) and next prime (39953).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 39945 - 2³ = 39937 is a prime.

39945 is a lucky number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1317 + ... + 1346.

It is an arithmetic number, because the mean of its divisors is an integer number (7992).

39945 is a Friedman number, since it can be written as 9+39*4^5, using all its digits and the basic arithmetic operations.

2³⁹⁹⁴⁵ is an apocalyptic number.

It is an amenable number.

39945 is a deficient number, since it is larger than the sum of its proper divisors (23991).

39945 is a wasteful number, since it uses less digits than its factorization.

39945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2671.

The product of its digits is 4860, while the sum is 30.

The square root of 39945 is about 199.8624527019. The cubic root of 39945 is about 34.1838369643.

It can be divided in two parts, 399 and 45, that multiplied together give a triangular number (17955 = T₁₈₉).

The spelling of 39945 in words is "thirty-nine thousand, nine hundred forty-five".