195639919 has 4 divisors (see below), whose sum is σ = 195763120. Its totient is φ = 195516720.

The previous prime is 195639901. The next prime is 195639931. The reversal of 195639919 is 919936591.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 919936591 = 7 ⋅131419513.

It is a cyclic number.

It is not a de Polignac number, because 195639919 - 2²⁵ = 162085487 is a prime.

It is a super-2 number, since 2×195639919² = 76549955812653122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (195639949) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 59187 + ... + 62404.

It is an arithmetic number, because the mean of its divisors is an integer number (48940780).

Almost surely, 2^195639919 is an apocalyptic number.

195639919 is a deficient number, since it is larger than the sum of its proper divisors (123201).

195639919 is a wasteful number, since it uses less digits than its factorization.

195639919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123200.

The product of its digits is 590490, while the sum is 52.

The square root of 195639919 is about 13987.1340524069. The cubic root of 195639919 is about 580.5226353352.

The spelling of 195639919 in words is "one hundred ninety-five million, six hundred thirty-nine thousand, nine hundred nineteen".