399837985 has 16 divisors (see below), whose sum is σ = 488980800. Its totient is φ = 313777216.

The previous prime is 399837979. The next prime is 399838081. The reversal of 399837985 is 589738993.

It is a cyclic number.

It is not a de Polignac number, because 399837985 - 2⁵ = 399837953 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 172011 + ... + 174319.

It is an arithmetic number, because the mean of its divisors is an integer number (30561300).

Almost surely, 2^399837985 is an apocalyptic number.

399837985 is the 11545-th octagonal number.

It is an amenable number.

399837985 is a deficient number, since it is larger than the sum of its proper divisors (89142815).

399837985 is a wasteful number, since it uses less digits than its factorization.

399837985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2960.

The product of its digits is 14696640, while the sum is 61.

The square root of 399837985 is about 19995.9492147785. The cubic root of 399837985 is about 736.7068082337.

The spelling of 399837985 in words is "three hundred ninety-nine million, eight hundred thirty-seven thousand, nine hundred eighty-five".