399171639 has 16 divisors (see below), whose sum is σ = 543628800. Its totient is φ = 260454336.

The previous prime is 399171581. The next prime is 399171649. The reversal of 399171639 is 936171993.

It is not a de Polignac number, because 399171639 - 2⁷ = 399171511 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399171649) 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, 36402 + ... + 46080.

It is an arithmetic number, because the mean of its divisors is an integer number (33976800).

Almost surely, 2^399171639 is an apocalyptic number.

399171639 is a deficient number, since it is larger than the sum of its proper divisors (144457161).

399171639 is a wasteful number, since it uses less digits than its factorization.

399171639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9974.

The product of its digits is 275562, while the sum is 48.

The square root of 399171639 is about 19979.2802422910. The cubic root of 399171639 is about 736.2973302214.

The spelling of 399171639 in words is "three hundred ninety-nine million, one hundred seventy-one thousand, six hundred thirty-nine".