194566661 has 4 divisors (see below), whose sum is σ = 194606412. Its totient is φ = 194526912.

The previous prime is 194566643. The next prime is 194566663. The reversal of 194566661 is 166665491.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 166665491 = 5189 ⋅32119.

It can be written as a sum of positive squares in 2 ways, for example, as 125776225 + 68790436 = 11215^2 + 8294^2 .

It is a cyclic number.

It is not a de Polignac number, because 194566661 - 2¹⁴ = 194550277 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 (194566663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11300 + ... + 22733.

It is an arithmetic number, because the mean of its divisors is an integer number (48651603).

Almost surely, 2^194566661 is an apocalyptic number.

It is an amenable number.

194566661 is a deficient number, since it is larger than the sum of its proper divisors (39751).

194566661 is an equidigital number, since it uses as much as digits as its factorization.

194566661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39750.

The product of its digits is 233280, while the sum is 44.

The square root of 194566661 is about 13948.7153888808. The cubic root of 194566661 is about 579.4591281555.

The spelling of 194566661 in words is "one hundred ninety-four million, five hundred sixty-six thousand, six hundred sixty-one".