194393813 has 2 divisors, whose sum is σ = 194393814. Its totient is φ = 194393812.

The previous prime is 194393809. The next prime is 194393831. The reversal of 194393813 is 318393491.

Together with next prime (194393831) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 147306769 + 47087044 = 12137^2 + 6862^2 .

It is a cyclic number.

It is not a de Polignac number, because 194393813 - 2² = 194393809 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (194393413) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97196906 + 97196907.

It is an arithmetic number, because the mean of its divisors is an integer number (97196907).

Almost surely, 2^194393813 is an apocalyptic number.

It is an amenable number.

194393813 is a deficient number, since it is larger than the sum of its proper divisors (1).

194393813 is an equidigital number, since it uses as much as digits as its factorization.

194393813 is an evil number, because the sum of its binary digits is even.

The product of its digits is 69984, while the sum is 41.

The square root of 194393813 is about 13942.5181728409. The cubic root of 194393813 is about 579.2874851397.

The spelling of 194393813 in words is "one hundred ninety-four million, three hundred ninety-three thousand, eight hundred thirteen".