399486509 has 2 divisors, whose sum is σ = 399486510. Its totient is φ = 399486508.

The previous prime is 399486497. The next prime is 399486523. The reversal of 399486509 is 905684993.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 399120484 + 366025 = 19978^2 + 605^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-399486509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (399486559) 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, 199743254 + 199743255.

It is an arithmetic number, because the mean of its divisors is an integer number (199743255).

Almost surely, 2^399486509 is an apocalyptic number.

It is an amenable number.

399486509 is a deficient number, since it is larger than the sum of its proper divisors (1).

399486509 is an equidigital number, since it uses as much as digits as its factorization.

399486509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2099520, while the sum is 53.

The square root of 399486509 is about 19987.1586024627. The cubic root of 399486509 is about 736.4908785482.

The spelling of 399486509 in words is "three hundred ninety-nine million, four hundred eighty-six thousand, five hundred nine".