399043549 has 4 divisors (see below), whose sum is σ = 399613500. Its totient is φ = 398473600.

The previous prime is 399043543. The next prime is 399043577. The reversal of 399043549 is 945340993.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 945340993 = 3257 ⋅290249.

It can be written as a sum of positive squares in 2 ways, for example, as 126562500 + 272481049 = 11250^2 + 16507^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-399043549 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 399043499 and 399043508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399043543) 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 in 3 ways as a sum of consecutive naturals, for example, 283924 + ... + 285325.

It is an arithmetic number, because the mean of its divisors is an integer number (99903375).

Almost surely, 2^399043549 is an apocalyptic number.

It is an amenable number.

399043549 is a deficient number, since it is larger than the sum of its proper divisors (569951).

399043549 is an equidigital number, since it uses as much as digits as its factorization.

399043549 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 569950.

The product of its (nonzero) digits is 524880, while the sum is 46.

The square root of 399043549 is about 19976.0744141586. The cubic root of 399043549 is about 736.2185650942.

The spelling of 399043549 in words is "three hundred ninety-nine million, forty-three thousand, five hundred forty-nine".