399989999 has 16 divisors (see below), whose sum is σ = 415451520. Its totient is φ = 384864480.

The previous prime is 399989983. The next prime is 399990001. The reversal of 399989999 is 999989993.

It is a cyclic number.

It is not a de Polignac number, because 399989999 - 2⁴ = 399989983 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 (399989959) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1208264 + ... + 1208594.

It is an arithmetic number, because the mean of its divisors is an integer number (25965720).

Almost surely, 2^399989999 is an apocalyptic number.

399989999 is a deficient number, since it is larger than the sum of its proper divisors (15461521).

399989999 is a wasteful number, since it uses less digits than its factorization.

399989999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 710.

The product of its digits is 114791256, while the sum is 74.

The square root of 399989999 is about 19999.7499734372. The cubic root of 399989999 is about 736.8001590104.

The spelling of 399989999 in words is "three hundred ninety-nine million, nine hundred eighty-nine thousand, nine hundred ninety-nine".