19965 has 16 divisors (see below), whose sum is σ = 35136. Its totient is φ = 9680.

The previous prime is 19963. The next prime is 19973. The reversal of 19965 is 56991.

It is not a de Polignac number, because 19965 - 2¹ = 19963 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1810 + ... + 1820.

It is an arithmetic number, because the mean of its divisors is an integer number (2196).

2¹⁹⁹⁶⁵ is an apocalyptic number.

19965 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

19965 is a deficient number, since it is larger than the sum of its proper divisors (15171).

19965 is an equidigital number, since it uses as much as digits as its factorization.

19965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41 (or 19 counting only the distinct ones).

The product of its digits is 2430, while the sum is 30.

The square root of 19965 is about 141.2975583653. The cubic root of 19965 is about 27.1283328176.

The spelling of 19965 in words is "nineteen thousand, nine hundred sixty-five".