399031665 has 16 divisors (see below), whose sum is σ = 639173376. Its totient is φ = 212576000.

The previous prime is 399031663. The next prime is 399031679. The reversal of 399031665 is 566130993.

It is not a de Polignac number, because 399031665 - 2¹ = 399031663 is a prime.

It is not an unprimeable number, because it can be changed into a prime (399031663) 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 15 ways as a sum of consecutive naturals, for example, 936 + ... + 28265.

It is an arithmetic number, because the mean of its divisors is an integer number (39948336).

Almost surely, 2^399031665 is an apocalyptic number.

It is an amenable number.

399031665 is a deficient number, since it is larger than the sum of its proper divisors (240141711).

399031665 is a wasteful number, since it uses less digits than its factorization.

399031665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30120.

The product of its (nonzero) digits is 131220, while the sum is 42.

The square root of 399031665 is about 19975.7769561036. The cubic root of 399031665 is about 736.2112565283.

The spelling of 399031665 in words is "three hundred ninety-nine million, thirty-one thousand, six hundred sixty-five".