39969 has 6 divisors (see below), whose sum is σ = 57746. Its totient is φ = 26640.

The previous prime is 39953. The next prime is 39971. The reversal of 39969 is 96993.

It can be written as a sum of positive squares in only one way, i.e., 32400 + 7569 = 180^2 + 87^2 .

It is not a de Polignac number, because 39969 - 2⁴ = 39953 is a prime.

It is a super-2 number, since 2×39969² = 3195041922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39929) 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, 2212 + ... + 2229.

2³⁹⁹⁶⁹ is an apocalyptic number.

It is an amenable number.

39969 is a deficient number, since it is larger than the sum of its proper divisors (17777).

39969 is a wasteful number, since it uses less digits than its factorization.

39969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4447 (or 4444 counting only the distinct ones).

The product of its digits is 13122, while the sum is 36.

The square root of 39969 is about 199.9224849786. The cubic root of 39969 is about 34.1906817745.

It can be divided in two parts, 3996 and 9, that added together give a triangular number (4005 = T₈₉).

The spelling of 39969 in words is "thirty-nine thousand, nine hundred sixty-nine".