195661 has 8 divisors (see below), whose sum is σ = 209664. Its totient is φ = 182160.

The previous prime is 195659. The next prime is 195677. The reversal of 195661 is 166591.

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

It is not a de Polignac number, because 195661 - 2¹ = 195659 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (195691) 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 7 ways as a sum of consecutive naturals, for example, 991 + ... + 1171.

It is an arithmetic number, because the mean of its divisors is an integer number (26208).

2¹⁹⁵⁶⁶¹ is an apocalyptic number.

It is an amenable number.

195661 is a deficient number, since it is larger than the sum of its proper divisors (14003).

195661 is a wasteful number, since it uses less digits than its factorization.

195661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 251.

The product of its digits is 1620, while the sum is 28.

The square root of 195661 is about 442.3358452579. The cubic root of 195661 is about 58.0543485814.

It can be divided in two parts, 1956 and 61, that multiplied together give a triangular number (119316 = T₄₈₈).

The spelling of 195661 in words is "one hundred ninety-five thousand, six hundred sixty-one".