399999247 has 2 divisors, whose sum is σ = 399999248. Its totient is φ = 399999246.

The previous prime is 399999227. The next prime is 399999317. The reversal of 399999247 is 742999993.

It is a weak prime.

It is an emirp because it is prime and its reverse (742999993) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-399999247 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (399999217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199999623 + 199999624.

It is an arithmetic number, because the mean of its divisors is an integer number (199999624).

Almost surely, 2^399999247 is an apocalyptic number.

399999247 is a deficient number, since it is larger than the sum of its proper divisors (1).

399999247 is an equidigital number, since it uses as much as digits as its factorization.

399999247 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9920232, while the sum is 61.

The square root of 399999247 is about 19999.9811749911. The cubic root of 399999247 is about 736.8058373818.

The spelling of 399999247 in words is "three hundred ninety-nine million, nine hundred ninety-nine thousand, two hundred forty-seven".