194728309 has 2 divisors, whose sum is σ = 194728310. Its totient is φ = 194728308.

The previous prime is 194728279. The next prime is 194728333. The reversal of 194728309 is 903827491.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 192238225 + 2490084 = 13865^2 + 1578^2 .

It is a cyclic number.

It is not a de Polignac number, because 194728309 - 2¹⁵ = 194695541 is a prime.

It is a super-2 number, since 2×194728309² = 75838228651998962, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (194728109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97364154 + 97364155.

It is an arithmetic number, because the mean of its divisors is an integer number (97364155).

Almost surely, 2^194728309 is an apocalyptic number.

It is an amenable number.

194728309 is a deficient number, since it is larger than the sum of its proper divisors (1).

194728309 is an equidigital number, since it uses as much as digits as its factorization.

194728309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108864, while the sum is 43.

The square root of 194728309 is about 13954.5085545855. The cubic root of 194728309 is about 579.6195572862.

The spelling of 194728309 in words is "one hundred ninety-four million, seven hundred twenty-eight thousand, three hundred nine".