399665711 has 4 divisors (see below), whose sum is σ = 399721752. Its totient is φ = 399609672.

The previous prime is 399665683. The next prime is 399665719. The reversal of 399665711 is 117566993.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 117566993 = 1933 ⋅60821.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-399665711 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399665719) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15440 + ... + 32213.

It is an arithmetic number, because the mean of its divisors is an integer number (99930438).

Almost surely, 2^399665711 is an apocalyptic number.

399665711 is a deficient number, since it is larger than the sum of its proper divisors (56041).

399665711 is an equidigital number, since it uses as much as digits as its factorization.

399665711 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56040.

The product of its digits is 306180, while the sum is 47.

The square root of 399665711 is about 19991.6410281898. The cubic root of 399665711 is about 736.6009873218.

The spelling of 399665711 in words is "three hundred ninety-nine million, six hundred sixty-five thousand, seven hundred eleven".