399387641 has 2 divisors, whose sum is σ = 399387642. Its totient is φ = 399387640.

The previous prime is 399387629. The next prime is 399387643. The reversal of 399387641 is 146783993.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 287641600 + 111746041 = 16960^2 + 10571^2 .

It is a cyclic number.

It is not a de Polignac number, because 399387641 - 2¹⁴ = 399371257 is a prime.

It is a Sophie Germain prime.

Together with 399387643, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 399387641.

It is not a weakly prime, because it can be changed into another prime (399387643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199693820 + 199693821.

It is an arithmetic number, because the mean of its divisors is an integer number (199693821).

Almost surely, 2^399387641 is an apocalyptic number.

It is an amenable number.

399387641 is a deficient number, since it is larger than the sum of its proper divisors (1).

399387641 is an equidigital number, since it uses as much as digits as its factorization.

399387641 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 979776, while the sum is 50.

The square root of 399387641 is about 19984.6851613930. The cubic root of 399387641 is about 736.4301160558.

The spelling of 399387641 in words is "three hundred ninety-nine million, three hundred eighty-seven thousand, six hundred forty-one".