39681 has 6 divisors (see below), whose sum is σ = 57330.
Its totient is φ = 26448.
The previous prime is 39679. The next prime is 39703. The reversal of 39681 is 18693.
It can be written as a sum of positive squares in only one way, i.e., 25281 + 14400 = 159^2 + 120^2
It is not a de Polignac number, because 39681 - 21 = 39679 is a prime.
It is a super-4 number, since 4×396814 = 9917230888295444484, which contains 4444 as substring. Note that it is a super-d number also for d = 2.
It is a plaindrome in base 7.
It is not an unprimeable number, because it can be changed into a prime (39631) by changing a digit.
It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2196 + ... + 2213.
It is an arithmetic number, because the mean of its divisors is an integer number (9555).
It is a Proth number, since it is equal to 155 ⋅ 28 + 1 and 155 < 28.
239681 is an apocalyptic number.
It is an amenable number.
39681 is a deficient number, since it is larger than the sum of its proper divisors (17649).
39681 is a wasteful number, since it uses less digits than its factorization.
39681 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 4415 (or 4412 counting only the distinct ones).
The product of its digits is 1296, while the sum is 27.
The square root of 39681 is about 199.2009036124.
The cubic root of 39681 is about 34.1083624569.
It can be divided in two parts, 3968 and 1, that added together give a square (3969 = 632).
The spelling of 39681 in words is "thirty-nine thousand, six hundred eighty-one".