399942218 has 12 divisors (see below), whose sum is σ = 649610838. Its totient is φ = 184588560.

The previous prime is 399942211. The next prime is 399942227. The reversal of 399942218 is 812249993.

It can be written as a sum of positive squares in 3 ways, for example, as 179211769 + 220730449 = 13387^2 + 14857^2 .

It is not an unprimeable number, because it can be changed into a prime (399942211) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 591293 + ... + 591968.

Almost surely, 2^399942218 is an apocalyptic number.

399942218 is a deficient number, since it is larger than the sum of its proper divisors (249668620).

399942218 is a wasteful number, since it uses less digits than its factorization.

399942218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1183289 (or 1183276 counting only the distinct ones).

The product of its digits is 279936, while the sum is 47.

The square root of 399942218 is about 19998.5553978281. Note that the first 3 decimals coincide. The cubic root of 399942218 is about 736.7708195683.

The spelling of 399942218 in words is "three hundred ninety-nine million, nine hundred forty-two thousand, two hundred eighteen".