39997 has 8 divisors (see below), whose sum is σ = 43776. Its totient is φ = 36432.

The previous prime is 39989. The next prime is 40009. The reversal of 39997 is 79993.

It is a happy number.

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

It is not a de Polignac number, because 39997 - 2³ = 39989 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is a congruent number.

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

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 828 + ... + 874.

It is an arithmetic number, because the mean of its divisors is an integer number (5472).

2³⁹⁹⁹⁷ is an apocalyptic number.

39997 is a gapful number since it is divisible by the number (37) formed by its first and last digit.

It is an amenable number.

39997 is a deficient number, since it is larger than the sum of its proper divisors (3779).

39997 is a wasteful number, since it uses less digits than its factorization.

39997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107.

The product of its digits is 15309, while the sum is 37.

The square root of 39997 is about 199.9924998594. The cubic root of 39997 is about 34.1986639242.

39997 divided by its sum of digits (37) gives a triangular number (1081 = T₄₆).

It can be divided in two parts, 399 and 97, that added together give a triangular number (496 = T₃₁).

The spelling of 39997 in words is "thirty-nine thousand, nine hundred ninety-seven".