391617399 has 4 divisors (see below), whose sum is σ = 522156536. Its totient is φ = 261078264.

The previous prime is 391617367. The next prime is 391617407. The reversal of 391617399 is 993716193.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 993716193 = 3 ⋅331238731.

It is not a de Polignac number, because 391617399 - 2⁵ = 391617367 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 (391617329) 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, 65269564 + ... + 65269569.

It is an arithmetic number, because the mean of its divisors is an integer number (130539134).

Almost surely, 2^391617399 is an apocalyptic number.

391617399 is a deficient number, since it is larger than the sum of its proper divisors (130539137).

391617399 is a wasteful number, since it uses less digits than its factorization.

391617399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130539136.

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

The square root of 391617399 is about 19789.3253801134. The cubic root of 391617399 is about 731.6229600716.

The spelling of 391617399 in words is "three hundred ninety-one million, six hundred seventeen thousand, three hundred ninety-nine".