195639 has 4 divisors (see below), whose sum is σ = 260856. Its totient is φ = 130424.

The previous prime is 195599. The next prime is 195659. The reversal of 195639 is 936591.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 936591 = 3 ⋅312197.

It is a cyclic number.

It is not a de Polignac number, because 195639 - 2⁷ = 195511 is a prime.

It is a D-number.

195639 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (195659) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32604 + ... + 32609.

It is an arithmetic number, because the mean of its divisors is an integer number (65214).

2¹⁹⁵⁶³⁹ is an apocalyptic number.

195639 is a deficient number, since it is larger than the sum of its proper divisors (65217).

195639 is an equidigital number, since it uses as much as digits as its factorization.

195639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65216.

The product of its digits is 7290, while the sum is 33.

The square root of 195639 is about 442.3109765764. The cubic root of 195639 is about 58.0521726350.

The spelling of 195639 in words is "one hundred ninety-five thousand, six hundred thirty-nine".