399138079 has 4 divisors (see below), whose sum is σ = 399337984. Its totient is φ = 398938176.

The previous prime is 399138059. The next prime is 399138097. The reversal of 399138079 is 970831993.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 970831993 = 83 ⋅11696771.

It is a cyclic number.

It is not a de Polignac number, because 399138079 - 2²⁷ = 264920351 is a prime.

It is a super-3 number, since 3×399138079³ (a number of 27 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399138029) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 96927 + ... + 100960.

It is an arithmetic number, because the mean of its divisors is an integer number (99834496).

Almost surely, 2^399138079 is an apocalyptic number.

399138079 is a deficient number, since it is larger than the sum of its proper divisors (199905).

399138079 is a wasteful number, since it uses less digits than its factorization.

399138079 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 199904.

The product of its (nonzero) digits is 367416, while the sum is 49.

The square root of 399138079 is about 19978.4403545422. The cubic root of 399138079 is about 736.2766951291.

The spelling of 399138079 in words is "three hundred ninety-nine million, one hundred thirty-eight thousand, seventy-nine".