399243193 has 2 divisors, whose sum is σ = 399243194. Its totient is φ = 399243192.

The previous prime is 399243139. The next prime is 399243227. The reversal of 399243193 is 391342993.

It is a happy number.

Together with previous prime (399243139) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 235070224 + 164172969 = 15332^2 + 12813^2 .

It is an emirp because it is prime and its reverse (391342993) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 399243193 - 2²¹ = 397146041 is a prime.

It is not a weakly prime, because it can be changed into another prime (399243133) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199621596 + 199621597.

It is an arithmetic number, because the mean of its divisors is an integer number (199621597).

Almost surely, 2^399243193 is an apocalyptic number.

It is an amenable number.

399243193 is a deficient number, since it is larger than the sum of its proper divisors (1).

399243193 is an equidigital number, since it uses as much as digits as its factorization.

399243193 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 157464, while the sum is 43.

The square root of 399243193 is about 19981.0708671983. The cubic root of 399243193 is about 736.3413228855.

The spelling of 399243193 in words is "three hundred ninety-nine million, two hundred forty-three thousand, one hundred ninety-three".