39861 has 12 divisors (see below), whose sum is σ = 59488. Its totient is φ = 25704.

The previous prime is 39857. The next prime is 39863. The reversal of 39861 is 16893.

It is not a de Polignac number, because 39861 - 2² = 39857 is a prime.

It is a Duffinian number.

39861 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39863) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 336 + ... + 438.

2³⁹⁸⁶¹ is an apocalyptic number.

It is an amenable number.

39861 is a deficient number, since it is larger than the sum of its proper divisors (19627).

39861 is a wasteful number, since it uses less digits than its factorization.

39861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152 (or 149 counting only the distinct ones).

The product of its digits is 1296, while the sum is 27.

The square root of 39861 is about 199.6521975837. The cubic root of 39861 is about 34.1598585152.

It can be divided in two parts, 39 and 861, that added together give a square (900 = 30²).

The spelling of 39861 in words is "thirty-nine thousand, eight hundred sixty-one".